187 



HARRIS TO HERRICK. 



Cambridge, Jan. 1, 1841. 



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

 have been revised by HaKclay and other Enghsh entomologists ? 

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

 the antennas, 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, 0. trntici^ etc. In 

 Diomyza Megerle (^Lasioptera^ 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 Avhitish 

 stigma ; species, L. berberina, albipennis, picta, etc. In Lasiop- 

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

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

 of the tarsi is long ; species, L. ohfuscata. 



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



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



on accoimt 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 piiparium^ 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, 

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

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

 the insect came 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 Avhich 

 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 {Tipidaf cerealis) of Europe, or a species 



