NO. 2242. MORPHOLOGY OF THE 8TREP8IPTERA— PIERCE. 



405 



EXTEKNAL STRUCTUKE. 



TRIUNGULINID. 



The triimgulinid or first larva (fig. 1) of the Strepsiptera re- 

 sembles most in form the larvae of the Dipterous family Cyrtidae, 

 of which the first stage of Pterodontia fiavipes Gray has been de- 

 scribed. This larva, of course, differs from the Strepsiptera by being 

 legless and without mandibles. The first larvae of the Meloidae and 

 Ehipiphoridae are very different in appearance. Those of Meloidae 

 have the tarsus consisting of three claws (figs. 2, 3), while the Rhi- 

 piphoridae have a single claw at the base of a pulvillus (fig. 4). 



The Strepsipterous hexapod larva is a well-organized larva with 

 head, 3 thoracic segments, and 10 abdominal segments. The eyes 



Fig. 1.— Stylops swenki. 

 Ventral view of tei- 

 ungulinid size 0.158 mm. 



Fig. 2.— Meloid triungu- 

 LiN. Ventral view. 



Fig. 3. — Meloid triungu- 

 LiN. Ventral view . 



consist of rather large ocelli in a group. The largest ocellar lens in 

 proportion to the size of the head is found in the hexapod larva of 

 Stichotrema daUatorr-eannm [^\. 67, fig. 3). It has two pair of 

 smaller ocelli. Large spots of pigment can be seen under the lenses. 

 The antennae of Stichotrema are three- jointed, with an arista on 

 the side of the second (pi. 67, fig. 5). The mouth parts consist 

 externally of a pair of mandibles, which in Stichotrema are very 

 large and extend backward. There is a chitinization resembling that 

 of Dipterous larvae surrounding the pharynx (pi. 67, figs. 2-5). 

 The legs consist of coxa, femur, tibiae, and one- jointed clawless 

 tarsus. The episternal sclerites are quite distinct in Stichotrema (pi. 

 67, fig. 3). The first seven abdominal segments are normal in all 

 species. The eighth, ninth, and tenth are variously modified. The 

 tenth bears a pair of very long stylets (pi. 67, figs. 1, 2). 



The larva of C allipharixenos muiri has five pair of ocelli, with each 

 one clearly outlined as a separate eye. The tarsi are one-jointed with 

 three terminal filaments or claws (pi. 68, figs. 4-7). 



