520 Cc. H. RICHARDSON 
head has disappeared, the mouth parts have taken the form of 
the ordinary Ichneumonid larva and there is a great reduction 
in size. 
Ratzeburg (’44) describes the larval stages of the Braconid 
Microgaster nemorum Hrt., an ectoparasite of lepidopterous 
larvae. The first stage larva is small, with twelve segments. 
The head and caudal appendage are not noticeably modified 
and no tracheae are present. The second larva is larger and 
the silk glands and mesenteron are conspicuous. The caudal 
segment bears a spiny knob-like swelling which Ratzeburg be- 
lieves to be a respiratory organ, since there is no tracheal system 
at this stage. The mouth parts are very simple. The tracheae 
arise during the third larval stage and the silk glands extend into 
the caudal segment but not into the caudal swelling. Between 
this and the pupal stage there are two less distinctly marked 
transitional stages. 
de Filippi (’51) has described the larval stages of an uniden- 
tified Pteromalid reared as a secondary parasite from the eggs of 
Rhynchites betuleti. The first larval form is of the cyclopoid 
type with a long furcated caudal appendage and a fringe of long 
spines at the juncture of the anterior with the following seg- 
ments. The larva moves about in the egg by means of the 
furcated appendage which it lashes briskly. The second larva 
increases in size, due to the growth of an ‘internal visicle’ (un- 
doubtedly an allusion to the enlarged mesenteron) and _ loses 
its mobility. Finally it is reduced to a mere sac with an ante- 
rior constriction. There may be some doubt as to whether the 
author really had a species belonging to the family Pteromalidae, 
since the type of larval development suggests strongly that of 
the Proctotrypoidea. 
Metschnikoff (’66) and Ganin (’69) found the cyclopoid larva 
in a species of the Proctotrypoid genus Teleas. The second 
author also described the development of the Proctotrypoid, 
Polynema (species not given) and several species belonging to 
the genus Platygaster both of which showed a definite hyper- 
metamorphosis. Three distinct larval forms were observed in 
Polynema. The first stage larva hatches without any visible 
