528 . ©. H. RICHARDSON 
stage larva is of the usual hymenopterous type. The mouth 
parts are very different from those of the preceding stages, and 
consist of a pair of strong mandibles supported by two sets of 
heavily chitinized ridges, the transverse ones reaching nearly to 
the lateral margins of the head. The mouth opening is hardly 
distinguishable. Below it is the circular labium. with chitinized 
edges. | 
A very interesting paper by D. Keilin and G. de la Baume 
Pluvinel (’13) on the larval forms of the Cynipoid, Eucoila keilini 
Kieffer, has recently come to my notice. This hymenopteron 
has an extraordinary first stage larva which lives within the 
body cavity of its dipterous host, Pegomyia winthemi Meig. 
In outline it resembles somewhat the ‘spindle-shaped’ larva of 
Teleas, but the head does not have an anterior snout-like pro- 
jection, nor are rows of bristles visible upon the dorsum. More 
striking however are the three pairs of long slender appendages 
on the ventrum of the thoracic region which easily distinguish 
this larva from any previously described. The mouth iscircular 
and chitinized and mandibles are absent. There are two conical 
papillae on the ventral surface of the head which may represent 
either the maxillary or labial palpi. The body is conical in form 
with twelve visible segments. The posterior segment is pro- 
duced into a single caudal appendage as long as the body, at the 
base of which a spinose appendage projects ventralward. The 
region about it appears to be covered with small chitinous scaies. 
Circulatory and respiratory organs are wanting. The advanced 
larva is of the usual form common among the Cynipids and 
agrees very well with the prevalent hymenopterous type. 
The authors were not able with the material at hand to dis- 
cover the intermediate stage or stages which must surely inter- 
vene between the bizarre first stage larva and the more gen- 
eralized advanced larva. 
There are many striking resemblances in structure between 
the primary larva of Eucoila keilini and those of the Procto- 
trypids, Teleas and Platygaster, but the number and form of the 
thoracic appendages and shape of the head suggest another larval 
type which will be called the Eucoilaform larva. 
