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 Sphinz, are but little advanced in their development; the brain is 
smaller than in pupz 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, Meloé. 
Or THE FEMALE STYLOPS. 
The structure of the female Stylops (Tas. 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 antennz ; 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- 
