NOTES ON SPERCHEUS EMARGINATUS, ETC. 215 
long-lost Spercheus. Elated with success, Mr. Billups went 
again, a few days afterwards, to the same place, and was again 
rewarded in his search, and this time brought home two females 
carrying their very singular bag of eggs. ‘’his season he has 
worked the same ditch several times during the months of June 
and July, and again met with the insect in sufficient quantity to 
spare myself and other friends type specimens. ‘This year males 
and females were captured, but the majority being females (almost 
all of which had the egg-pouch attached to the abdomen), he feels 
convinced that period of the year is the breeding season. The 
pouch-carrying is most interesting; the bag itself is made of 
a thick silky material of a pale brown colour, several shades 
lighter than the insect itself, very closely spun or woven, and 
slightly inflated, like the bag of a spider. It covers the whole of 
the abdomen from the middle pair of legs, and is seemingly held 
in place by the hinder pair, it being greatly indented or pinched 
in by the knee-joint of the tibie. 
Spercheus evidently does not, like most other water-beetles, 
attach her nest to any of the varied water-plants which abound in 
ditches, but carries it about with her until such time as the eggs 
hatch and the young larve come forth; these are little black 
things about one line in length, and much resembling other larve 
of aquatic Coleoptera. Each of these bags contains about half a 
hundred eggs, and in two instances Mr. Billups has counted over 
seventy eggs in one pouch. He tells me he does not think that 
the larve are plant-feeders, as has been stated, but decidedly 
carnivorous, whatever the imago may be. 
Mr. Rye, in his work on ‘ British Beetles,’ states that in a few 
hours after disclosing the larvee from the sac or pouch, the female 
at once forms another. I question this very much, and believe 
that only one bag and one set of eggs is produced during a season. 
My friend has, at the time I am writing, several females which 
he has kept above two months in his aquarium, and which 
hatched their larve. They were captured in the early part of 
June, and although they are in the company of males, and are 
frequently seen in cop., and have plenty of weed and shelter, 
still there is not as yet (August), at any rate, the slightest sign of 
a second sac being formed; but no doubt we shall know more 
about this insect shortly. 
Another interesting capture from the same locality is Hydrous 
