352 



JOURNAL OF ECONOMIC ENTOMOLOGY 



\yo\. 8 



lactucce Kalt. The latter is very common in the fall on a species of 

 milkweed around Corvallis, Oregon. On approaching an Aphis the 

 larva makes a quick dart for it, inserts its piercing mouthparts, and 

 sucks the blood from the victim. 



The accompanying table gives some data on the life history of three 

 of the larvae. 



Duration of the Various Stages 



Larva No. 



Hatched 



1st moult 



2nd moult 



3rd moult 



Pupated 



Emerged 



1 



Nov. 23, 1913 



Nov. 26, 1913 



Nov. 28, 1913 



Dec. 7. 1913 



Dec. 7, 1913 



Dec. 21. 1913 



2 



Nov. 11, 1913 



Nov. 15, 1913 



Nov. 20, 1913 



Nov. 22, 1913 



Nov. 22, 1913 



Dec. 8, 1913 



3 



Nov. 22, 1913 



Nov. 26, 1913 



Nov. 28, 1913 



Dec. 6, 1913 



Dec. 6, 1913 



Dec. 21, 1913 



The duration of the larval stage and instars varies considerably 

 according to the nature and quantit}^ of the food supply and the rapid- 

 ity with which it feeds. Also the temperature. The larval period was 

 found to average fourteen days. 



The larva is sort of spindle-shaped, tapering toward the caudal end. The mature 

 larva measures 7.5 mm. in length. The head is strong and bears large sharp curved 

 grasping and blood sucking mouthparts. The antennae are composed of three annu- 

 lated segments, the rings being very close together and not distinct so that several 

 cross lines occur connecting the different rings. The eyes are dark brown and almost 

 black. A dark brown line runs thi'ough the eyes as well as the center of the head. 

 The legs are whitish and the feet possess suckers which are sort of bell-shaped and 

 located between the claws. The abdomen is light amber in color with darker mark- 

 ings. On each side of the dorsal aspect there is a discontinuous line, each thoracic, 

 and the first few anterior abdominal segments possessing an irregularly shaped mark- 

 ing, brown in color. These markings are intersected by the thoracic and abdominal 

 sutures. There is also a line which runs down the center of the dorsum from the 

 head to the cauda. The underneath parts are pale amber colored fading to a whitish 

 color approaching the sides. The larva is slightly pubescent. The sucker at the 

 caudal end of the abodmen is used, as in the case of the larvae of the Coccinellidce, for 

 anchorage. 



When ready to pupate, the larviB as a rule seek some crevice in the 

 bark, although cocoons were found in clustered leaves of apple curled 

 by Aphis, and on the under surface of the leaves of currant and hop 

 vines. Anthracnose cankers on trunks and limbs of apple trees make 

 desirable places for hibernation. Each larva upon finding a suitable 

 place immediately begins to construct a very thin, loosely woven co- 

 coon. When the cocoon is constructed it continues contracting, moults 

 for the last time and pupates. The cocoon is 5 mm. in length. 



