66 
Psyche 
[April 
BIOLOGICAL NOTES ON PARTHENOGENETIC MACRO- 
SIPHUM TANACETI LINNAEUS 
(APHIDIDiE, HOMOPTERA ) 1 
By Leopoldo B. Uichanco 
College of Agriculture, university of the Piiillipines 
Los Banos, P. I. 
The data on which the present paper is based have been 
collected while I was conducting experiments on Macrosiphum 
ta?iaceti, in connection with another problem. The work was 
done at the Bussey Institution during the earlier part of the 
summer of 1921. A few of the facts brought out in the discussion 
are somewhat fragmentary, and require more thorough investi- 
gation; but, in view of the scarcity of such records of aphid 
behavior in the literature, they have been introduced here, in 
the hope that they may help to stimulate further research along 
these lines. 
I. Ecdysis. There are no appreciable differences in the 
behavior of Macrosiphum tanaceti during the four successive 
molts. No attempt, therefore, will be made in the present paper 
to describe the methods separately for each ecdysis. Preliminary 
to the process, the nymph ceases to feed for a few minutes, and 
in the meantime holds with its claws on the surface of the sup- 
porting part of the plant. The position of the insect during 
molting has always been found to be such that the head points 
toward the ground. The legs are spread far apart, so that the 
prothoracic pair is directed anterolaterallv with reference to the 
insect’s body; the mesothoracic, ectolaterally; and the meta- 
thoracic, posterolaterally. The haustellum is held close to the 
sternum. The subcaudal portion of the abdomen almost touches 
the surface of the plant. The antennae are directed posteriorly, 
and are subparallel to the lateral margin, but diverge at an angle 
of about thirty degrees above the dorsal surface of the body. A 
longitudinal mesal rupture then appears at the head, adjoining 
iContribution from the Entomological Laboratory of the Bussey Institution, Harvard 
University. No. ioo. 
