60 



TKE CLASS OF INSECTS. 



Fis. C3. 



that of the young larva, and stand ont free from the body. 

 The head is much smaller in proportion to the rest of the 

 body, and bent more upon the breast. 



The Larva (Fig. 62) 

 when hatched is about 

 five hundredths of an 

 inch in length. The 

 head is now free and 

 the antenuiXJ stand out 

 free from the front. 

 The thorax has greatly 

 diminished in size, 

 while the abdomen has 

 become wider, and the 

 limbs very long; and 

 the numerous minute tubercles, seen in the preceding stage, 

 have given origin to hairs. The dorsal vessel can now, for the 

 first time, be seen. When in motion, the resemblance 

 to a spider is most striking. The flow of blood to 

 the head, and the return currents through the lacunar 

 or venous circulation along the side of the body Avere 

 easily observed. The vessels Avere not crowded Avith 

 blood disks, the latter being few in number, only one 

 or two passing along at a time. Two currents, pass- 

 ing in opposite directions, were observed in the legs. 



Fig. 03. Side view of the head of Uie larva of Diplax before the first moult, c, 

 deciduous tubercles terminating in a slender style; tlicir use Is unknown: tliey 

 have not been observed in tlic full-grown larva, e, the compound eyes. 1, the 

 three jointed antenna>, the terminal joint nearly three times as long as the two 

 basal ones. 2, tlie mandibles, and also enlarged, showing the cutting edge divided 

 into four teeth. 3, maxill:i! divided into two lobes: (/, tlie outer and anterior lobe, 

 2-jiiinted, tlie basal joint terminating in two seta?; and «, the inner lobe concealed 

 from view, in its natural (losition, by the outer lobe, r^ 4, the base or pedicel of 

 the second maxillas, or labium, the expanded terminal portion being drawn sepa- 

 rately; rf and rt, two movable stout styles representing, perhaps, the labial palpi: 

 the lobe to which they are attached is nuiltidentate, and adapted for seizing 

 prey; on the right siile the two styles are appressed to the lobe, x rei)resents, 

 perhaps, the ligula; but we have not yet studied its homologies carefully: this 

 ))art is attached to a transversely linear piece soldered to the main part of the 

 labium, y, the 11th abdominal ring, with its pair of conical anal styles, c, the 

 Just tarsal joint and pair of long slender claws. 



Fir;. (14. The pui)a of Diplax, having riidiinentarywings, in which the eyes are 

 much larger, and the legs much sliortcr than in the lecently hatched larva; in- 

 troduced to be compared with ihe young larva. Figs. 57-04, oriyiiud. 



