60 ' [March, 



NOTES ON THE BIOLOnY OF DREPANEPTERYX PHALJENOIDES, L. 

 BY PROFESSOR DR. M. STANDFUSS, ZURICH. 



" Several times near Ziiricli I have met with the very mobile larvae 

 of a lighter or darker brown colour with a greasy gloss, measuring 

 when full grown 12 to 15 mm. long. These lai-vse do not cover them- 

 selves with the skins of the plant lice they have sucked dry, in this 

 respect differing from their i-elatives of the genus Hememhius. They 

 were found in populous colonies of Lachnus fayi, L., on the under-side 

 of the leaves of Fagiis silvatica, L. Often also this gluttonous enemy 

 of the plant lice was foiuid on the foliage of plum trees, Prnmis 

 ilomestica, L. (Zwetschen) and Prumis inH'difia, L. (Pflaumen), 

 amongst ApJiis 'pruni, F., a species present in great numbers nearly all 

 the year round. 



With us it occurs still more numerously in the great colonies 

 of Schizoneura ulmi, L. This plant-louse causes a blister-like swelling, 

 and a yellowish discoloration of the leaves of JJlmus campestris, L., 

 infested by it. G-radually the leaves become rolled at the margin 

 downwards and inwards, and so form a pod-like sheltering hollow 

 space in which the full grown larvae of Drepaneptery;c not rarely fix 

 their pupal web. I further discovered Schizoneura lanigera, Hansm. — 

 the " Blutlaus " of the apple tree — to be a S2:)ecially favourite food of 

 the laiwa of this fine Hemerobiid. My good friend Dr. Fr. Ris, of 

 Rheinau, sent me repeatedly, apple-twigs much infested by this Schi- 

 zonenra, for use in my lectures on insects injiu'ious to agriculture and 

 forestry. The first of these consignments in May, 1904, produced 

 alone 32 imagos, and later sendings, also, always contained a number 

 of individuals of this Neuropteron. 



The larva of this species I found here, in Eastern Switzerland, 

 between the beginning of May and the middle of July. In autumn I 

 was never able to observe larvae, so that in our region we should have 

 decidedly only one generation of B. pliaJienoides. 



Pupation takes place according to the warmth of the season, and 

 probably also according to the available supply of plant-lice, between 

 the middle of May and the middle of July, in rolled-up leaves, or some- 

 times in crannies on tree stems, or even on the ground. 



The neat, rather wide-meslied cocoon, consists of two parts, the 

 inner ordinarily oval btit sometimes approaching a spherical form ; the 

 outer a looser enveloping web. It is produced from the contents of the 

 rectal glands modified into spinning glands. The larva lies rolled up 

 in a ball whilst engaged in this work. It is verv absorbing to observe 



