SCIENTIFIC SUMMARY. 
333 
anxious to secure the co-operation of English and American naturalists, and 
hopes that they will remember the zoological station in the distribution of 
their papers. 
Specimens of Stylops on Andrena atriceps. — At the meeting of the Ento- 
mological Society on May 3, Sir Sidney Smith Saunders, C.M.G., President, 
exhibited male specimens of Stylops, taken by himself in the pupa state on 
Andrena atriceps, at Hampstead Heath, on the 6th, 9th, and 17th April 
last. Mr. Enoch, who had been there on the 6th, at an earlier hour (be- 
tween nine and ten o’clock), had been still more successful, having captured 
seventeen males ; one of which, however, was taken after 2 p.m. The 
President drew attention to the remarkable difference observable in the 
cephalothorax of the females in these specimens, as compared with those 
met with on Andrena convexiuscula, and remarked on the importance of 
avoiding confounding the species obtained from different Andrense : Stylops 
Spencii having been described from A. atriceps , while S. Thwaitesii had been 
described from A. convexiuscula. Mr. Smith believed that eventually a. 
great many species would be found to inhabit this country, and that as many 
as a dozen different species would probably be found on the genus Andrena 
alone, independently of those on the genus Halictus. 
Gammaridce in Lake Baikal. — Dr. B. N. Dybowsky has described ninety - 
seven species of Gammarids from Lake Baikal. They include one Swedish 
species, G. ( Pallassa ) cancelloides ; and also the G. neglectus of the lake is 
hardly distinct from G. pidex. The species occur at all depths, the greatest 
depth dredged, 1,373 metres, affording them as abundantly as the littoral 
zone, though fewer in species. The species of small depths are mostly vividly 
coloured ; those at greater depths are less bright in colour, and the kinds 
from depths greater than 700 metres are more or less whitish in tint. 
Notes on some Parasitic Worms. — At a late meeting of the Philadelphian 
Academy of Science, Professor Leidy remarked that Mr. Henry Horn, assist- 
ant superintendent at the Zoological Garden, had given to him several speci- 
mens of worms recently passed by a Bengal tiger. There are three males and 
eight females, and they appear to be the Ascaris mystax, which has been 
found in many other feline species, including the domestic cat and the lion. 
The characters of the worms from the tiger are as follows : — Body almost 
equally tapering towards the extremities. Female — Cephalic and indexed, 
with long narrow semi-lanceolate alse. Caudal end straight ; tail short, 
conical, subacute. Male — Cephalic end straight, alated. Caudal end in- 
dexed, and furnished with a row of about two dozen minute round papillae 
on each side ventrally ; tail short, conical, acuminate. Length of females 
from 2 to 3| inches; thickness from f to § line. Length of males from 13 
to 16 lines ; thickness from f to f line. Professor Leidy further remarked that 
Mr. Thomas Meehan had submitted to his examination some worms which 
had been found in an apple. They consisted of one entire individual and 
the anterior half of a second, and apparently pertain to the Mermis acuminata , 
a long thread- worm which has been discovered infesting the larvse of many 
insects. Among others it is parasitic in the larva of the codling-moth, or 
fruit-moth of the apple, which readily accounts for its presence in the fruit. 
Twenty-dve years ago (Proc. 1850, 117) he had described a worm, belonging 
to the collection of the Academy, and labelled as having been obtained 
