June, '15] 



MOZNETTE: THE BROWN LACE-WING 



351 



The determinations of the Aphids used were made by Prof. H. F. 

 Wilson to whom I am also indejDted for suggestions in this work. 

 The determination of the lace-wing was made for this department by 

 Mr. Nathan Banks, of the United States National Museum, Washing- 

 ton, D. C. He described this species in his paper entitled New North 

 American Neuropteroid Insects, Transactions of the American Ento- 

 mological Society, XXIV. 



On November 3, 1913, numerous eggs and larvae were found among 

 colonies of Aphis sorbi Kalt. on apple trees in the experimental orchard 

 of the Oregon Agricultural College. The eggs are laid singly on the 

 lower surface of the leaves. They may be found placed indiscrimi- 

 nately over the lower leaf surface, but most of them are deposited next 

 to the midrib, lateral vein or in the axil of the two. They are laid 

 horizontally or on end, usually the former. 



The egg is ovoid, white, changing to a light amber in the course of development and 

 growth, and measures .92 mm. in length and .40 mm. in width. The surface is retic- 

 ulated and at one end is located a small disc-shaped micropyle. 



On November 29, 1913, a number of apple leaves free from eggs were 

 tagged on a small apple tree. Many eggs were found in the orchard 

 on this date. The tagged leaves were observed each day and Decem- 

 ber 1, 1913, three leaves were found each with a single egg. These 

 leaves were placed in vials to ascertain the incubation period. The 

 eggs developed, and hatched on December 10, 1913, the duration of 

 the egg stage being nine days. 



The newly hatched larva is somewhat different from that of the 

 mature larva in that it is distinctly white in color, and the mouthparts 

 are much more prominent than in the later instars. The eyes are a 

 faint brown. It measures 2 mm. in length. Upon hatching, the 

 larva emerges from the egg at one end, and remains motionless for a 

 very short period, after which it immediately becomes very active 

 in search of food. 



The larva moults three times, twice before spinning its cocoon and 

 once just before it transforms to the pupa. The third larval exuvium 

 is found in the cocoon. I have observed that the larvae of Hemero- 

 hius pacificus develop much more rapidly in warm than in cool weather. 

 Under the latter conditions, they seem to become more sluggish and 

 show a reluctance to feed. The larvae did not show any real disposi- 

 tion to cover themselves with Aphis skins, though they frequently 

 became entangled in the hairs and feet, and were involuntarily carried 

 about. ' 



The larvae were supplied with an abundance of Aphis, consisting of 

 Aphis sorhi Kalt., Macrosiphum lycopersici Clark; and Amphorophora 



