336 Mr. Newport on the Natural History 



and retarded its changes ; the tissue itself is thin and partially destroyed ; the 

 air-sacs at the sides of the abdomen, which are exceedingly large in the male 

 imago Sphinx, are but little advanced in their development ; the brain is 

 smaller than in pupae of the same age ; and the male organs of reproduction, 

 the testes, — which always become united into one mass immediately the larva 

 Sphinx has changed to a pupa, — remain widely separated as in the larva, their 

 form only being somewhat altered. 



These facts show, that insects infested with internal parasites are often 

 sterile. The Sphinx dies of its injuries before assuming the imago state; 

 while the bee lives on to perpetuate the enemy of her tribe, and be herself 

 the means of transporting it to the nidi of her own or of others' young, as she 

 conveys thither also the parasite, Meloe. 



Of the Female Stylops. 



The structure of the female Stylops (Tab. XIV. fig. 20) is as full of interest as 

 are the effects of her presence on the organization of the bee. I was anxious 

 to examine most carefully, in the specimen I had obtained, that portion which 

 is of a corneous texture, and protrudes between the abdominal segments of 

 the bee (A), and which. Dr. Siebold has shown, is not merely the head, as 

 naturalists have supposed, but the entire cephalo-thorax. This most certainly 

 is the fact. On the concave, or dorsal surface of this part, I have been able to 

 recognise the four segments which constitute the head and thorax of the 

 young larva firmly united together into one region. In the first, the true 

 head, there are no eyes or antennae ; and in the others, the prothorax, meso- 

 thorax and metathorax, there are not even the slightest indications of legs or 

 other appendages. When viewed by strong transmitted light, I found the 

 latter two segments, as in the enlarged abdomen (B), crowded with ova in 

 various stages of development, converging towards the middle line at the 

 anterior of the mesothorax, which corresponds to the oviduct on the ventral 

 surface. The ventral surface is convex, and divisible like the dorsal into its 

 original segments. At the sides of the anterior one are two quadrangular, 

 flattened, corneous bodies (a), which, with Siebold, I regard as rudimentary 

 mandibles. Between these is a cruciform opening, the buccal orifice, bounded 

 posteriorly by two thin plates {b), probably the labial, divided by a longitu- 



