Videnskabelige meddelelser

Videnskabelige meddelelser


it will hardly ever be searched for in vain. Usually it sits in

great numbers at the base of tlie roots. I have often gathered

them in a number of 20— 30 upon one single plant.

The egglaying process takes especially place in May— June;

then the above named carpet of roots along the shores of our

swamps and ponds can be stained scarlet by the enormous mas-

ses of eggs. The newly hatched lårvæ I have not seen myself;

but in June—July I have seen the pond-skaters of a pond by

hundreds carry the red pear shaped larval stages. Using my Zeis

binocular lenses in my boat I have convinced myself that of the

entire total of the Gerridiv on a pond only a very few keep clear

of the larvæ. The phenomenon lasts until August — September; then

the bugs are again free from their parasites. As far as i know

the hibernation does not take place upon the insect. More thorough

explorations may show whether Limnochares hibernates as nymph

or as fullgrown or, as much as 1 suppose, in both these stages.

Further we do not know whether the parasitic stages can be ac-

complished upon Gerridæ only and whether these can be infested by

Limnochares larvæ only, out of all the Hydrachnid larvæ. It is

only established that the red pearshaped bodies upon Gerridæ, as

Duges indicates, may give Limnochares, as I have often held

Gerridæ with larvæ in my aquaria and have got nymphs of Lim-

nochares hatched from these pearshaped stages. Unfortunately it

is very difficult to keep the Gerridæ in aquaria; they all die too

soon. Further investigations may show whether Duges is right

when he indicates, that the 6 legged larva normally leaves the

host, going to pupation otherwise.

Fam. Eylaidæ.


Our knowledge of the development of the species of the genus

Eylæis is but very small. According to the litterature one should

think that the species were able to live parasitic on the most dif-

ferent insects; unfortunately the reports do not make a more solid

impression. I for my part do not feel convinced that the authors

have always had lujlæis stages before them.

The eggs are mentioned by Neuman (1880, p. 107). Pier-

More magazines by this user
Similar magazines