302 MODERN CLASSIFICATION OF INSECTS. 
at their full growth, and some of which were even ready to burst forth 
as imagines; but it is not improbable that the Stylops larva, during 
its feeding state, may possess more powerful oral instruments, which 
are subsequently withdrawn, just as is the case with the mandibles of 
the larva of Diptera. 
In such uncertainty, the fact that the sexual distinctions of these 
insects have not been observed, or, rather, that all the specimens which 
have yet been examined in the winged state are apparently males 
(judging from the antennee and abdominal appendages), together 
with the circumstance that some individuals remain unchanged at 
the time when others assume the winged (male ?) form, are deserving 
of consideration ; as is also the following observation. In the spring 
of 1836, whilst keeping numerous stylopised individuals of Andrena 
Gynnana and parvula, in the hopes of rearing the Stylops, I observed 
a number of excessively minute hexapod creatures creeping amongst 
the hairs of the abdomen of the bees (which were evidently much 
annoyed at their presence), and which, with a strong lens, I distinctly 
saw making their way through the transverse impression near the ex- 
tremity of the upper side of the head of the larva of the Stylops* (jig. 
93. 18.) ; and in this manner every one of the many larve of the Stylops, 
which I hoped to rear, perished. Anxious, however, to obtain more 
knowledge of these parasites of the parasite, I opened the bodies of some 
of the bees thus attacked, so as to expose the moist and fleshy body 
of the larvee of the Stylops, when I was surprised to find the latter 
filled with an extraordinary number of them; some, as though not 
sufficiently developed, lying in an arched position; and others, nearer 
the head of the Stylops larva, struggling towards the place of exit 
above mentioned. The transparent skin of the larva permitting them 
to be clearly visible, I do not hesitate in stating that there must have 
been far beyond a hundred of these creatures in each Stylops larva. 
The body is long and flattened (fig. 93. 19. one highly magnified), 
rather narrow towards the tail, which is furnished with two very long 
setee ; the head is semicircular and flat, with two dark eye-like patches 
at each posterior angle, and apparently destitute of antennz; the 
body is composed of thirteen segments, including the head, and ex- 
cluding the two small fleshy tubercles upon which the anal setze are 
placed: the first segment of the body is transverse, and applied 
* The Senator Van Heyden has observed the same circumstance in Xenos. 
( Trans. Ent. Soc. vol. i. p. 1xxiv.) 
