Videnskabelige meddelelser

booksnow2.scholarsportal.info

Videnskabelige meddelelser

45

Koch, P. carnea (C. L. Koch) and longipalpis (Krendowsky), nodata

(O. F. M.) Piersig (1900, p. 96—108) indicates that the larvæ

are parasitic upon difPerent aquatic insects or „Wasserkaferlarven"

further that the second pupa stage takes place upon water piants.

All more thorough investigations are wanting. Only with regard to

Piona carnea he reports that the pupa is ball shaped and that

P. longipalpis can occur in great nutnbers. Soar (1906, p. 361)

communicates that the hatching of the eggs takes 17 days. The

massy occurrence of a P/o/ia-species on a narrowly restricted local-

ity has also been observed here at Hillerød and at Frederiksdal.

In two different localities where the bottom of the pond was covered

with the aquatic leaves of Siiun latifolium the water really teemed

with P. longipalpis. With regard to Piona rotunda (Kramer)

Piersig (1900, p. \21) indicates that the whole development is

finished in the course of 10— 12 days and takes place in the

glassy substance around the eggs, the parasitic stage being totally

suppressed. Quite a similar account is given by Piersig (1900,

p. 118) with regard to P. fuscata.

With regard to Forelia Haller we do not know anything; only

for F. liliacea (O. F. M.) Piersig (1900, p. 175) indicates that it

is parasitic „auf Wasserinsekten".

Subfam. Aturinæ.

Also of the development of this family our knowledge is exceed-

ingly small. It restricts itself to the, in my opinion, quite valueless

indication that the sixlegged larva stage is parasitic upon aquatic

insects and that the second pupa stage takes place upon water

piants (Piersig, 1900). We find these indications with regard to

Axonopsis complanata (O. F. M) (p. 249), Mideopsis orbicularis

{O. F. M.) (p. 266), Midea orbiculala (O. F. M.) p. 271. Only for

Brachypoda nersicolor {O. F. M.) Piersig (1900, p. 253) indicates

that the parasitic stage is dropped out; the larvæ when hatched

from the eggs fasten themselves immediately to water piants and

metamorphoses into nymphs; they are stated never to be able to

conduct a freeswimming existence.

Subfam. ArrhenureUinæ.

The development is absolutely unknown.

;

More magazines by this user
Similar magazines