S^ 'new YOtlK: STA'l'E MUSEUM 



peculiar family has but a single genus, a single species, and is 

 represented by but a single specimen, which is now in the United 

 States National Museum. This family will fall in the couplet 

 with the h i r o n o m i d a e in the key given by Comstock 

 (1895), and by Williston (1896), but differs from all the members 

 of this family by its peculiar wing venation (pl.35, fig.29). The 

 description of the family was first given by Mr. Coquillett 

 (1899a). 



The eggs 



The eggs of moist of the O h i r o n o m i d a e are deposited 

 in water; some species in swift flowing water, others in sea or 

 lake water, while most of them lay them in stagnant pools or 

 ponds, or in slow flowing streams. The eggs of a few species are 

 deposited in bark, in manure, and in debris. Some species lay 

 them in strings resembling somewhat a mi nature string of toad's 

 eggs; while others lay them in clumps. The eggs themselves are 

 elongate, cigar-shaped, usually pointed at each end. They hatch 



in a few days. 



The larvae 



The larvae are worm-like, but vary somewhat in form with 

 the different genera. Most of them are aquatic, while a few live 

 in the earth, in manure, or under bark (pi. 16, fig.4 ; pi. 17, figs.l and 

 4;pl.l9,fig.9). 



Excepting some of the C e r a t o p oi g o n they are provided 

 with both thoracic and anal prolegs, and move by creeping in 

 a manner somewhat like a geometer larva, without, however, 

 such regularity, nor does the middle section hump up, but loops 

 irregularly to one side or the other. Many species are blood-red 

 in color, and hence are frequently known as blood-worms. They 

 have a distinct head with well-formed labrum, labium, epipharynx, 

 hypopharynx, mandibles and maxillae, the mandibles moving in 

 oblique planes. The body is distinctly segmented, -usually with 

 twelve joints besides the head, the three thoracic segments being 

 but little thicker than those of the abdomen. The twelfth seg- 

 ment is provided with a pair of prolegs, some caudal setae and 

 blood gills; sometimes there are two pairs of conspicuous blood 

 gills upon the ventral surface of the eleventh segment also. The 



