32 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
who called it PI. castorinus . Priority of publication was, however, ob- 
tained by Ritsema by a period of 14 days. Both these naturalists located 
the insect among the Fleas. In 1872 the American coleopterologist Le 
Conte pointed out that the beaver parasite was a Beetle, and his conten- 
tion was supported later on (1886) by Riley in a communication entitled 
c Systematic Relations of Platypsyllus as determined by the Larva/ 
Thus it seems that the beaver of the Old and New Worlds is infested 
hy parasitic beetles which, according to some, belong to the same species. 
In the skin of the Alaska beaver another parasitic beetle, Leptinilhis 
validus Horn, having only rudimentary eyes, has been found, and in the 
skin of mice a perfectly blind example of the same family, Leptinus 
testaceus Mull. 
Megnin has described two other beetles parasitic on Rodents, Arnbly- 
cpinns Jelslrii and A. Mniszechi , but the author holds that their real 
parasitism is not proved. 
Resemblance of an Insect-Larva to a Lichen-Fruit.* — Mr. G. E. 
Stone points out the remarkable resemblance — which may possibly be 
mimetic — between the larva of the elm-leaf beetle, Gossyparia ulmi, re- 
cently imported into the United States from Europe, and the apothece 
of a lichen, say, PJiyscia hypoleuca ; the resemblance extending to size, 
form, and colour. 
Social Wasps of Brazil.f — A short note by Dr. H. von Ihering is of 
interest, as, with the exception of one note by him, all the facts we know 
with regard to social wasps have been learnt from the observation of 
European species, In some genera the societies are not dissolved in 
winter, but are perennial. Unlike what happens in Polistes and Vespa , 
where each society has but one fecundated female, which is much larger 
than the workers, there are in the societies of Polybia a number of 
fecundated females, and these females do not differ from the workers in 
size. The presence of a number of fecundated females is an important 
fact, and represents a condition which is relatively primitive. At first, 
of course, there were no workers in a colony, but only males and females. 
Specialisation could not have started with the immediate reduction of 
the fecundated females to one queen, but there must have been a partial 
reduction in numbers. These fecundated females became reduced in 
number, and at the end of the process there was only one. In Polybia 
we see one of these stages — numerous fecundated females with no 
difference between them and the workers. 
Life-History of Larvae of (Estrus4 — Dr. Ruser reports that he 
found in four oxen, which gave the ordinary external signs of being 
affected by this fly, transparent larvae in the loose connective tissue 
between the oesophagus and the body-wall. It would appear that the 
larvae arc able to bore through the wall of the oesophagus, and so to 
make their w r ay to the great vascular trunks in the region of the neck. 
It would appear, therefore, that the view' that the larvae of this fly enter- 
hy the mouth is correct. 
* Bull. Torrey Bot. Club, xxiii. (1896) pp. 454-5. 
f Bull. Soc. Zool. France, xxi. (1896) pp. 195-62. 
i See Centralbl. f. Bakteriol. u. Parasitenk, xx. (1896) p. 548, 
