of the Oil Beetle, Meloe, and of the Strepsiptera. 343 



the whole on each segment are of equal length, so that the appearance of 

 the larva under the microscope strongly reminds us of the genus Polyxenus 

 among the Myriaj)oda, or of the larva of Attagenus or Dermestes amongst the 

 Coleoptera. The ninth segment of the abdomen, the thirteenth of the whole 

 body, is armed with a pair of elongated caudal styles or setae ; and the infe- 

 rior surface of the fourteenth or anal segment is soft, prehensile, and em- 

 ployed by the larva in locomotion, like the anal prolegs in other larvae. The 

 caudal styles are distinctly articulated to their segment by a large and a small 

 joint, but I have not been able to detect any articulation in the remaining 

 portion of these organs with the instrument I have employed, a triplet magni- 

 fying about 450 diameters. 



The legs are formed of a coa?a^ joint, a femur, a tibia, and a four-jointed tar- 

 sus. The coxa is a large and powerful joint ; the posterior one is much larger 

 than the others, and the whole are armed, each with four curved stiff spines. 

 The femur is also a strong joint, and has two small spines at its distal, or tibial 

 articulation. The tibia is elongated, slender, and somewhat clavated at its 

 articulation with the tarsus, where it has a short spine on its internal margin. 

 The tarsus is long and composed of four joints. The basilar joint is very 

 short, but the distal one is large and spatulate. It is in fact a double joint, 

 so that the true tarsal joint is the shortest, and the first metatarsal is the long- 

 est. The tarsi of the posterior pair of legs are much smaller and shorter than 

 those of the first and second pairs. The third and fourth terminal joints are 

 not spatulate, but are very narrow, weak and slender. This appears to be a 

 character common both to Stylops and Xenos. 



Locomotion of the Larva of Stylops. 



When the larva attempts to walk on a smooth surface, as on glass, it moves 

 very tardily, and its long tarsi are bent irregularly; but when attached to the 

 hairs or body of a bee, its power of locomotion is much greater. When climb- 

 ing up a hair it moves almost precisely like the larva oi Meloe, but very much 

 more slowly. It first shortens its segments and affixes itself firmly to the hair 

 with its anal prolegs, and then, elongating its body, steps onwards, making 

 use of its thoracic legs alternately in the act of progression. When left for a 

 few hours on some hairs from a bee, on the glass object-plate of a microscope, 



