886 



Journal of Agricultural Research 



Vol. VI, No. 23 



irpVfJ 



Fig 



aphid and sucks the body fluids until the aphid is dead and more or less 

 shriveled. The victim seldom notices the presence of the larva, judging 

 from outward indications. After the larva becomes one-third grown it 

 usually punctures the aphid at one of the articulations of the legs, a favorite 

 point of attack being at the membranous joint connect- 

 ing the tibia and femur (PI. CX, fig. 2). If the larva 

 attacks the aphid at an articulation as above described, 

 the latter seldom notices the attack; but if the proboscis 

 of the larva touches the wrong places, the aphid kicks 

 about more or less for a few seconds. As a rule, several 

 minutes are required for the larva to pump out most of 

 the body juices of the host, but this time varies, depend- 

 ing upon the relative sizes of the larva and its host. 

 The aphid is often discarded by the larva soon after it 

 has been killed and long before it has been sucked dry. 

 To the naked eye the larva of Aphidoletes meridionalis 

 (fig. 2) closely resembles such common cecidomyiids as 

 the cloverleaf midge (Dasyneura trifolii L,oew), but 

 differs slightly in coloration, being usually of a pale 

 orange, varying from pale pinkish to a rather deep 

 orange, and when mature measures approximately 3 

 The length of the larval period varies, depending upon 

 the temperature and food supply; but according to observations of the 

 writer it is between 7 and 1 1 days. 



When fully mature the larva spins a loose cocoon of silk mingled with 

 aphid remains, attaching it to the leaf between the veins ; or it descends 

 to the ground and at or near the surface spins 

 its cocoon (fig. 3), incorporating with it particles 

 of dirt and trash. The larva pupates shortly 

 after constructing the cocoon. The pupa (fig 

 4), which is of an orange color, resembles other 

 related cecidomyiids; it measures 2 mm. in 

 length and its cocoon is 2.25 mm. long and 

 1. 1 25 mm. wide. The length of the pupal 

 stage varies, according to observations, between 

 6 and 9 days. 



The adult (PI. CX, fig. 1) may be popularly 

 described as a small, frail midge, much resem- 

 bling, to the casual observer, {Dasyneura) Neo- 



cerata rhodophaga Coq. the destructive rose midge, or the clover-seed midge 

 (Dasyneura leguminicola Lintn.). Its length is approximately 1.4 mm. 

 for the male, and 1.8 mm. for the female; the body is pale and the abdo- 

 men has a decided pinkish tint. Copulation and egg laying seem to occur 



— Aphidoletes 

 meridionalis: Larva, 

 dorsal view. Great- 

 ly enlarged. 



mm. in length. 



Fig. 3. — Aphidoletes meridionalis: a, 

 Cocoon formed on surface of 

 ground; b, cocoon formed on a 

 leaf blade. 



