GALL APHIDS OF THE ELM. 22/ 



the 1st and 2nd joints slightly bulbous; 3rd either surpassing or equal- 

 ing in length the 4th, 5th and 6th together, which are subequal ; the ter- 

 minal joint usually the shortest, the apical sub-joint being normal, and 

 in some cases sufficiently constricted to resemble an additional joint; 

 joints 3, 4, and S rather distinctly annulated the constrictions being 

 generally quite deep, and producing a moniliform aspect, there being on 

 an average 22 such on joint 3. Tarsi with the basal joint distinctly 

 separated into a lobe, the claws strong, and in length twice the diameter 

 of the tarsus. Wings hyaline: front pair with the veins becoming obso- 

 lete at tips ; stigma subhyaline, either of a yellowish tinge or somewhat 

 dusky; stigmal vein starting from the middle of the stigma and normal- 

 ly curved ; cubital vein obsolete for nearly one-third its length, the fur- 

 cal forming with it almost a point; the terminal distance between first 

 and second discoidals equal to about five times that between their bases 

 (often rather more) ; terminal distance between furcal and cubital and 

 second discoidal veins subequal that between stigmal and furcal slightly 

 shorter, that between second and first discoidal one-third greater, and 

 about equal that between stigmal and tip of stigma. Hind wings with 

 the subcostal vein almost straight, there being no curve where it gives 

 off the discoidal veins, which are obsolete at their extreme base and not 

 confluent with it. (The wing venation is very constant. Out of nearly 

 100 specimens examined, I have found only an unusual .'shortening of the 

 cubital in two individuals). The larva and pupa in this third gencation 

 differ from the winged insect in being more reddish and in having the 

 antennae ringed with less distinct constrictions, in the legs being paler, 

 in the claws being stronger, and in the basal joints of tarsus being more 

 connate with the terminal joint. They have a distinct annulated eleva- 

 tion at each side posteriorly — a sort of pseudo-honeytube. When first 

 born they are of a pale dull yellow, and the antennal joints are more 

 nearly subequal in length. 



"Fourth generation. — That from the first winged females : Differs 

 from the preceding in the promuscis being much longer, in the antennae 

 having but five joints, the third being somewhat longest and the first 

 the shortest, but all often being of much more nearly equal length, with 

 no annulalcd constrictions. The color is more decidedly orange. When 

 newly hatched, the thickened end of the promuscis often extends one- 

 half the length of the body beyond anus. The legs are also long and 

 stout, and the basal joint of the tarsus is distinct, but not separated. 

 The capitate hairs are obsolete. It is born with an enveloping pellicle or 

 pseudovum, and though of a bright red with pale legs at first soon be- 

 comes brownish, with dark members. 



"Fifth generation. — The counterpart of the second. 



"Si.vth generation. — Second winged: Resembles the third, but u.siially 

 rather lighter colored, with the wing-veins, the spinous armature of 

 surfaces, and the constrictions of antennae less strong, and with the 

 third joint of antennae rather less in length than the terminal three 

 together. 



"Seventh generation. — True sexual individuals: Born within an egg- 

 like pellicle. With stout promuscis reaching to between middle and hind 



