June, '12] TOWNSEND: WHITE SCALE OF COTTON 261 



points will be fully investigated as soon as the proper facilities can 

 be had for carrying out the work. 



The oviposition of Aspidiotiphagus may be described here, as I 

 think it has not before been observed. Tilting a pill-box cover bearing 

 on the inside surface both the Apidiotiphagus and the active Hemi- 

 chionaspis larvae so that I could see the underside of the body of the 

 former, I was able to witness every stage in the act clearly and repeat- 

 edly with the 65x magnification of the binocular. The parasite 

 approaches an active larva and strokes it with her antennae to quiet it 

 and to determine the position of its head apparently. If on approach- 

 ing it she happens to be facing its head, I noted in several cases that 

 she turned so as to face the same way as the larva before advancing 

 to place the latter immediately under her abdomen with her feet on 

 each side of it. By this means she can tell whether the larva moves 

 during the act. The larva usualh' remain motionless, apparently 

 soothed by the preliminary antennal stroking into receiving the 

 insertion of the parasite's ovipositor. I noted in one instance that 

 the parasite attempted to insert the ovipositor into a larva that 

 happened to face in the opposite direction from herself, not having 

 taken the precaution to turn around before advancing to cover it, 

 whereupon the larva ran out between her hind legs and the ovipositor 

 slipped to the surface of the box cover, into which the parasite, uncon- 

 scious apparently of the escape of the larva, endeavored to force it. 

 The Aspidiotiphagus, being in position for the act, brings the tip of 

 the ovipositor with the tips of the two lateral ovipositor-guides to 

 the dorsal surface of the larva, usually about the center of the dorsum, 

 the guides being held in that position for a moment or two until the 

 point of the ovipositor has effected an entrance when they are allowed 

 to return to place approximated to the ventral surface of the abdomen 

 and the ovipositor is seen to remain as a minute long bristle stuck 

 into the body of the larva. It remains inserted in the larva's dorsum 

 but a few moments, evidently long enough only for the passage of a 

 single egg. The parasite then proceeds to find another larva, when 

 the operation is repeated. 



The habit which Aspidiotiphagus and probably certain other of 

 these smaller parasites have of ovipositing in the active coccid larvae 

 has an important bearing on the spread of the parasite species con- 

 cerned. As the active larval period is the only one during which these 

 coccids become dispersed from plant to plant, the advance of the host 

 assures the transportation of the parasite provided the latter is suffi- 

 ciently numerous at the origin of spread. 



Concerning other parasites available for the work here, the following 

 records of rearings from H. minor may be made: 



