258 QUARTERLY JOURNAL. 



its subdivlsionSj proposed by diflferent authors, those of Lalreille " 

 appear to be the most natural, and are the ones most referred to at 

 the present day. He divides the Tipulidte into five subordinate 

 groups, each differing somewhat from the others in the form of 

 the perfect insects, and still more in the habits of the larvae. 

 These groups are briefly characterized, as follows : 



1. Aquatic iTipulides. Antennae entirely covered [with hair. Larvae live in the 

 Water. 



2. Terrestrial Tipulides. Head elongated into a muzzle. Larvae inhabit the earth| 

 mostly living on the roots of plants. 



3. Fungivorous Tipulides. Two or throe ocelli ; trochanters elongated ; tibif 

 strongly spurred. Larvte feed on mushrooms. 



4. Tipulides of gall-nuts. No ocelli : trochanters of ordinary length ; liead no 

 prolonged to a muzzle ; antennee moniliform, clothed with short and scattered hair 

 Larvce generally feed in galls formed on vegetables. 



5. Floral Tipulides. Antennae short, perfoliated, of from only eight to tweh 

 joints; legs of ordinary length. Larva in dung-hills ; perfect insects on flowerSj 

 said to eat their buds. 



GENERIC CHARACTERS. 



It is to the fourth of the above groups that the insects under 

 consideration pertain. All the insects comprised in this group 

 are distributed in the following genera, the mogt prominent distinc 

 tive characters of each being appended. 



CERATOPOGoNk AntennjB with a tuft or bundle of hairs at their base. 

 PsYCHODA. Wings furnished with numerous nervures. 

 Cecidomyia. Wings with but three nervures. 



Lestremia. Like Cecidomyiaj but antennae only fifteen-jointed, and the first far^ 

 sal joint elongated. 



The wings and antennae, then, it will be perceived, furnish the 

 characters by which the genus cecidomyia is distinguished from 

 all the other Tipulidse. The antenncB are always longer than the 

 head, and frequently as long as the body ; they are slender and 

 thread-like, and composed of sixteen joints or more, each joinl 

 being of a rounded and often globular form, and, at least in tiie 

 females, verticillated with short hairs; that is, having a number 

 of hairs placed in a row around the joint, like the spokes of a 

 wheel in its hub. In the males, the number of joints is commonly 

 twenty-four, and these are clothed with minute hairs, but not al- 

 ways verticillated. 



The wings^ when the insect is at rest or walking, are not in- 

 clined in the form of a roof, as they are in the genus Psychoda; 

 but repose upon the back in a horizontal direction, like those of 



I 



