April, 1918] Parasites of Leaf-Hoppers 207 



the hairs can be seen resting back along the body, those of the 

 first segment pointing cephalad, those of the rest caudad. In 

 some species the peculiar cone-like structure is still present 

 in this stage. This is evidently peculiar to only those species 

 ovipositing in the abdomen of the host and it is characteristic 

 of at least four stages since in nearly mature larvae a series of 

 four, all telescoping more or less within each other, can be 

 seen. It has been found in parasites ovipositing in the abdomen 

 of Chlorotettix iinicolor nymphs, Deltocephalus inimicus nymphs 

 and adults, and Deltocephalus sayi adults. 



While in the sac the head of the dryinid larva is always 

 ventral and the caudal end of the body is curved upwards and 

 anteriorly lying dorsal to it. The spiracles of all the exuviae 

 are open, but are not connected in any way with those of any 

 of the larval spiracles. However, a trachea can be seen running 

 from the first spiracle of the third exuvium to the corresponding 

 spiracle of the larva itself, so that it is possible some air may be 

 taken in by the parasite in this way. The fifth instar is enclosed 

 laterally by the three exuviae and dorsally by the third only. 



Mature Larva. — The mature larvae vary in size, those studied 

 measuring from 1.5 mm. to 4 mm. in length. They are blunt 

 and wider posteriorly and more pointed anteriorly (Fig. 16). 

 They are variously colored, agreeing in many cases with the 

 color of their hosts. They may be various shades of green and 

 even light pink, but as a rule they are white. Aphelopus larvae 

 are quite pubescent, but those of the more highly specialized 

 types are almost without hairs. The head is distinctly separated 

 from the body and is light brown or grey in color. Thirteen 

 segments are visible not including the head. They are more or 

 less concealed by the folds in the skin. On the head (Figs. 

 17 and 18) dorsally the two black pigmented eyes, the rudi- 

 mentary antennae and the short arcuate labrum are visible. 

 The former may be but slightly pigmented and very indistinct, 

 even in a species that normally has pigmented eyes. The 

 labrum is covered with short spines and appears as a fleshy 

 projection from the side. The curved heavy mandibles are 

 very prominent. They are one-jointed and articulated from 

 a chitinized basal piece. In Neodryinus and Paradryinus the 

 cutting edge is crenulate or denticulate (Perkins, 1905), or it 

 may be notched in Gonatopus (Mik, 1880). The maxillae are 

 less distinct. Laterally they are represented as short truncate 



