187 



HAERIS TO HERRICK. 



Cambridge, Jan. 1, 1841. 



Are you aware that the genera Cecidomyia^ Lasioptera, etc., 

 have been revised by Haliday and other Enghsh entomologists ? 

 In Cecidomyia are now included those gall-gnats, etc., in which 

 the antennre, especially in the males, are long, and in which, more- 

 over, the joints are verticillate and pedicellate ; the basal joints 

 of the tarsi are very minute ; the wings (generally) have two 

 longitudinal and one furcate nervure ; species, C. tritici, etc. In 

 Diomyza Megerle (JLa^ioptera^ Div. A^ Meig.), the antennae are 

 short, the joints not verticillate nor pedicelled ; the basal joint 

 of the tarsi is short ; the wings have one longitudinal and one fur- 

 cate nervure ; the costa is thickened and black, with a whitish 

 stigma ; species, L. herhervna^ alhipennis, picta, etc. In Lasiop- 

 teryx Stephens (^Lasioptera, Div. B, Meig.), the antemiss and 

 the nervures of the wings are as in Diomyza ; the basal joint 

 of the tarsi is long ; species, L. obfuscata. • 



You will perceive that the Hessian Fly cannot go into Dio- 

 myza on account of its (male) antennae ; nor into Lasiopteryx 

 on account of the tarsi. As to the nervures of the wings, I 

 think that you will find them to vary somewhat in the species, 

 as they do in many other genera. 



I have no objection to calling the dried larva-skin of the 

 maggot of the Hessian Fly a puparium, though I think the 

 term pupa when applied to it rather incorrect. I supposed, of 

 course, that the included pupa had its own appropriate skin, 

 like the pupa of all other flies which are coarctate ; but I was 

 not prepared to believe implicitly in Mr. Havens' statement that 

 the insect canie out of the puparium before it threw off its 

 proper pupa skin. Is this true ? 



I have never supposed our barley insect, the larva of which 

 lives within the culms of the barley, was the same as the Ceci- 

 domyia destructor ; and am inclined to believe that it is either 

 the barley midge (Tipula? cerealis} of Europe, or a species 



