on the larva of Pelophila. 139 
ing long setz, the arrangement of which does not exactly 
correspond in the two cerci of the same individual 
(Fig. 10). 
COMPARATIVE MORPHOLOGY OF THE LARVA, 
As mentioned above, the genus Pelophila is classed, by 
its imaginal characters, with Leistus and Nebria. In the 
larval stage it resembles those genera in the possession of 
long, mobile cerci, as well as in the general structure of 
the antennze and mouth-parts. But it differs widely 
from them in its broad quadrate head and short legs with 
equal tarsal claws. The larva of Pelophila indeed shows 
relationships with various carabidous larve of widely 
separated genera. The form of the head, without the 
constricted neck so characteristic of the Nebriina, recalls 
that of Hlaphrus, and still more perhaps that observed in 
certain Harpaline genera, such as Broscus, Chlenius and 
Pterostichus.* The larva of Pelophila agrees with these 
latter in the insertion of the antennz over the base of the 
mandibles. ‘The head-appendages agree generally with 
those of the Nebriine larve, as well as with those of 
Hlaphrus ; in the proportional lengths of the segments 
of the maxillary galea Pelophila is intermediate between 
these two groups. The long paired sete of the labial 
ligula again recall the larval characters of Broscus and 
Chlenius. A character in which our larva is most clearly 
separated from the Nebriina is the comparative shortness 
of the legs, which by the arrangement of the spines and 
the equality of the two tarsal claws resemble those of 
Elaphrus and the Harpaline. It is remarkable that 
Amara seems the only other carabidous genus in which 
the larval tarsi are shorter than the tibiz. The abdominal 
cerci are the most unequivocal nebriine structures to be 
found in our larva. It is of some interest to note that 
while the cerci of the full-grown Pelophila grub closely 
resemble those of Nebria, in the young larva they are 
simpler, as in the full-grown grub of Leistus. As men- 
tioned above, these cerci are mobile in the full-grown 
larva, but not in the young. In the majority of cara- 
bidous genera these appendages appear to remain fixed 
throughout larval life. 
* Schigdte, “De Metamorphosi Eleutheratorum,” Pars. III. 
(Naturh. Tidsskr, iv. 1867.) 
