"How I Cut Down"

Page 1, 2, 3, 4, 5

So how could I cut my project down? The then conventional wisdom was that "Laphria" constituted a single large genus of very closely related flies, that could not be subdivided in any reasonable fashion. The 1965 Diptera Catalog had synonymized the old genus Bombomima with the group. This presented a real problem. I could not just revise, say, all the species whose names began with A through J. No committee would ever accept such a dissertation. And although I have concentrated my work on taxonomy, even then I had read Hennig's seminal book on cladistic theory from cover- to-cover, and was a phylogenetist at heart. I could not accept an arbitrary division.

Also I half believed that Laphria could not be broken up--mainly because I had a great deal of trouble reliably identifiying specimens--and consequently only worked my way slowly into the huge mass of material. There was only one key available that included most of the species. This key was part of S. W. Bromley's unpublished 1934 Ph.D. dissertation, which covered the subfamily Laphriinae in North America as a whole. In addition to covering both "Laphria" and Bombomima his dissertation, Bromley had described many of the species of these two genera in a series of papers dating from the 1920's through 1951. His key had the big disadvantage of not working. This was partially because it was based on color: the specimens I was examining were extremely variable, and represented an infinitely wider variety of localities than the few specimens which Bromley examined. A second disadvantage of Bromley's key was that it did not cover the sizable number of species he had described later in his career.

Lack of accurate identifications was a complicating factor. Specimens that had been identified as identical by separate (and distinguished) workers, were obviously different from one another. And flies that had been identified as being different from one another appeared nearly the same. To top everything off, female flies--a full half of the total-- were in many cases considered to be unidentifiable. As one example of the ruling confusion, the paratype series of one species I examined, eventually proved to contain specimens of two additional species, which had already been described. Now a paratypes is a sort of "voucher' specimen an author sets aside when he describes a new species. They are about the most reliably identified specimens you can get--and yet here, and in several additional cases as well, they were incorrectly placed. I do not mean to belittle the particular workers involved; the misidentified paratypes were females, which were nearly indistinguishable from one another externally. When I made the identifications, I removed and macerated the terminalia

Believe me, you have not lived until you have seen boxes on boxes packed with thousands upon thousands of apparently similar flies, all awaiting your identification, which--were it possible to provide, would take years of work, and which you secretly suspect can never be forthcoming. Even now, after mastering the entire original genus in one way or another, on a bad day a Schmidt box full of unidentified flies can still give me the shudders.

Fortunately, a solution eventually presented itself.

It was a direct result of my growing familiarity with the world asilid fauna, through the literature and understanding of terminalic structure mentioned earlier. After examining a majority of the flies, I realized that the species fell into four well-defined groups. One of these was roughly equivalent to Laphria as understood in Europe. These were the species that had first been misplaced in the genus Dasyllis and which later had been assigned to their own genus, Bombomima. A second group was exactly equivalent to Choerades in Europe. The two continents even shared a species, Choerades gilvus (Linnaeus). And two even more distinct groups had never been categorized. This knowledege was as valuable as it was unexpected. Neither Bromley or even Frank Hull, who wrote the 2-volume Robber Flies of the World, had realized the same groups were masquerading under different names in the two regions. It was also a God-send. I now had a way out. I promptly chose to limit my dissertation to the flies that I planned to reassign to other genera, that is, to the species within Choerades as well as those in two new groups. I therefore set the true Laphria aside.

This greatly simplified life. The group I would forgo, hereafter to be known as Laphria s. str., was the largest assemblage of species, and by far the hardest to distinguish from one another. In fact I had come to regard it as the asilid analogue to the Hawthornes among plants (genus Crataegus), that is, a group so diverse and new geologically that the majority of species were more in the process of formation, than already formed. The males of only about five of the thirty described species of Laphria s. str. could be identified by examining the terminalia externally. So without a lengthly dissection of every specimen they could only be grouped by color, which, unfortunately, is extremely variable. And two facts greatly complicated this type of identification: 1) the males and females are sexually dimorphic, and differ in pattern from each other in subtle ways, and 2) it is likely that the species frequently hybridize with one another. Hybridization is currently known to occur between L. virginica and L. posticata.

Further, this group contained the largest number of undescribed species. In what work I did I identified five (as opposed to ten all together in the other three groups combined), which I will eventually be describing. But I suspect that I have just scratched the surface. I would not be surprised if there are not another ten still awaiting discovery, which so closely resemble described types as to be virtually indistinguishable.

And last, by forgoing this group, at one blow I eliminated half of the 20,000 specimens from further consideration. For these reasons, my strategy was ultimately successful. It allowed me to pretty much finish detailed revisions of the other three groups.

Next page "The Long Grind"

Back to Laphriini Page Introduction