DEVELOPMENT OF A HYMENOPTEROUS PARASITE 523 
mead). The first of these to be mentioned, Synopeas rhanis 
Walker, possesses four larval forms, the cyclopoid, the inter- 
mediate, the secondary and the tertiary larvae. The cyclopoid 
larva resembles in superficial habitus the nauplius stage of cer- 
tain crustaceans. The body consists of an enlarged cephalo- 
thorax composed of the head and at least the first thoracic seg- 
ment, bearing a pair of short antennae, a pair of small chitinized 
first maxillae, which are mere tubercles, a heavily chitinized labium 
consisting of several rows of tooth-like points and below this a 
smaller chitinized ligula. The first thoracic segment has a pair 
of two-jointed appendages, which are probably sensory in func- 
tion. The last abdominal segment terminates in two long ser- 
rated appendages. The intermediate larva shows a degeneration 
of the mandibular muscles and a contraction of the tissues of 
the appendages so that the latter now lie on a level with the 
body surface. The mesenteron enlarges enormously and invades 
the abdominal region. The intermediate larva undergoes an 
ecdysis and appears as the secondary larva. In this stage, the 
mesenteron is large and brown in color, the other tissues form- 
ing a clear zone around it. Metamerism is indicated by eight 
parallel muscle bands. The mandibles are now reduced to minute 
claw-like appendages. The first maxillae are represented by 
small oval tubercles behind the mandibles. The second maxillae 
are indistinct and have already fused with the labium, which is 
present in the form of a minute chitinized crest. Stigmatic 
openings and tracheae are present but the latter do not possess 
a lumen. The tertiary larva is characterized by distinct exter- 
nal segmentation. The mandibles are sharp and heavily chitin-. 
ized. The stigmata are very distinct. 
Trichacis remulus Walker agrees nen well in its larval stages 
with the preceding species. 
Inostemma piricola Kieffer possesses a cyclopoid, an inter- 
mediate and a secondary larva, the latter being segmented and 
homologous with the tertiary larva described for Synopeas. 
In a species of Inostemma from Cecidomyia aenophila Haimh., 
Marchal has observed a cyclopoid larva comparable to that of 
Inostemma piricola Kieffer. 
JOURNAL OF MORPHOLOGY, VOL. 24, NO. 4 
