208 ENTOMOLOGISK TIDSKRIFT 1914. 
is armed with two rows of spines (fig. 2a), a modification 
for the purpose of grasping the prey. Even the nymphae 
have a few spines on the femora (fig. 2b). 
It is probable that the other species, P. formicetorum, 
which lives in the nests of ants also is predaceous; if so, 
the genus differs in its food-habits from the other genera of 
‘the Anfhocoridae, which are said to be herbivorous. 
3. The larva of Pachygaster minutissima ZETT. is common 
in the neighbourhood of Stockholm under the bark of dead 
pines and fir-trees. From a comparison between the larva 
and that of P. farsalis ZETT. it is evident, that the number 
and position of the bristles on the body offers good specific 
characteristics. For the morphology of the body and the 
head vide fig. 3a—c; there are only spiracles on the pro- 
torax and on the 11th abdominal segment; they are delineated 
in fig. 4a and b. From the structure of the mouthparts (fig. 
5 and 6) it is evident, that the larvae feed om semiliquid 
substances, fungi, and other matter which they scrape off 
from the surface of the wood. 
4. The larva of Wedeterus signaticornis LW. is very com- 
mon in the burrows of barkbeetles in the vicinity of Stock- 
holm, as a matter of fact found regularly with them. The 
author was able to ascertain, that it fed on the larvae and 
pupae, which it sucked out. In fig. 7 the larva, the anterior 
and posterior spiracles and the locomotorial discs are deli- 
neated, in fig. 8 the mouthparts. 
5. Cambium-miners have not been previously recorded 
from Sweden, wheres in Germany, Denmark and U. S. A. 
they have been observed repeatedly and belong to the genus 
Agromysa. Last summer, however, the exceedingly charac- 
teristic spots, arranged in concentrical rings, caused by them, 
were observed in young birch-trees and a microscopical investig- 
ation proved that they agreed in structure with those caused 
by the larva of A. carbonaria ZETT. This species occuring 
all over Sweden, it is very probable that it is responsible also 
for this damage. 
As, howewer, there are leaf-miners to be found in seve- 
ral groups of insects it would not be strange to find other 
groups than the Diptera even amongst the cambium-miners. 
