— 25 — 



Var. solitaria was reared by RUSCHKA and THIENEMANN (1) 

 from Agrionine-eggs in Stratiotes (1 spécimen from each egg), 

 and I hâve reared it from Erythromma na/as-eggs in Nuphar- 

 stalks Funkedam, and from Liraphoderes-eggs in Alisma Hjor- 

 teso at Hillerod (also one spécimen in each egg) — thus only in 

 small Odonate-eggs. 



The host eggs can be infested in ail developmental stages, 

 yet I hâve not found parasites in mature host-embryoes, which 

 agrées with the statemen's of RlMSKY-KoRSAKOW. This author 

 remarks that a female can lay up to 50 eggs. I hâve not seen 

 a Prestwichia lay so great a number, and a dissection of the 

 abdomen of newly hatched but fertile females of var. brevipen- 

 nis shcwed at most only 30 eggs. 



b 



E 



Fig. 3. — 'Prestwichia aqualica LUBB. 



A. Ovarial egg. — B. Deposited egg. — C. Egg containing an embryo in the yolk of the host egg. 



D. E. F. Free larvae in différent size, seen from the side. — (Ail figures enlarged X 60.) 



I have followed the development of var. brevipennis from 

 egg to imago. The ovarial egg ready for oviposition is fusiform, 

 pedunculate and measuring 0,222 mm. (fig. 3 A). Within a day 

 from the déposition the egg has increased very much in size, 

 up to 0,382 mm (a fact which is already known from the deve- 



(1) L. c, p. 83. 



