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ON VARIOUS SPECIES OF TRICEOPTEBYQIBJE NEW TO BRITAIN. 

 BT THE BET. A. MATTHEWS, M.A. 



There are certain species, or ratlier groups, in the genus Tricliop- 

 teryx, which seem involved in universal confusion. Of those now re- 

 corded for the iirst time as British, four are quite common in this 

 country, and may be found in any good collection mixed up with other 

 species. The discrimination of these diverse forms is mainly owing to 

 the exertions of an entomologist, often I think much underrated, I 

 mean M. V. Motschulsky, who in various parts of the " Bulletins de 

 Moscou," has described their differences in a manner for the most part 

 amply sufficient for recognition. It is much to be regretted that he has 

 not done this more fully, for I feel sure that most of those which he 

 has separated are genuine species. Take, for instance, the heterogeneous 

 group which is often seen bearing the common name of T. sericans ; by 

 the side of a broad depressed insect, with brown pubescence, you will 

 probably find a neat looking oval specimen, considerably convex and 

 very black ; while next to this appears a flat oblong example with long 

 legs and antennse ; not one of the three bearing the slightest resem- 

 blance to either of the others, except that in all the anteunae are nearly 

 black. To the first mentioned Motschulsky correctly applies the name 

 of " sericans, Heer " {dej)ressa, Grillm.) ; the second he makes a new 

 species, and calls "bovina;'" the third he clearly describes as the true 

 " picicornis, Mann." In each of these a microscopical examination will 

 reveal characters abundantly distinct ; so much so, that in larger insects 

 the most careless observer would not fail to perceive their difference. 



Again, if we look at the species which Motschulsky has separated 

 under the name of T. lata, the only matter of surprise will be that it 

 should have so long escaped the notice of others. In examining large 

 masses of T. fascicular is and its allies, I have often met with specimens 

 for which it was almost impossible to find a satisfactory position ; their 

 long brown pubescence and wide subquadrate shape disagreed altogether 

 with T.fascicularis, while on the other hand the absence of erect setae, 

 and other differences, seemed to forbid any association with T. grandi- 

 collis ; and, under the microscope, many essential characters appeared, 

 equally diverse from either species. But all these characters agreed 

 exactly with Motschulsky's description of T. lata. This separation at 

 once obviated all difi&culty in correctly classifying the group, and cleared 

 up the previous obscurity. 



T. brevis is another instance of a like nature ; this is always mixed 

 with T. pygmcea, although no two species of nearly the same size can 

 differ more strongflv. 



