422 Transactions. — Zoology. 



Genus Aleukodes, Latreille. 



Insects attacking plants, oviparous ; metamorphosis incom- 

 plete ; fixed in the earlier stages to leaves, free and active in 

 the adult stage, when they usually have a habit of rising in 

 a cloud when disturbed and settling again after a short 

 time. 



Adults of both sexes having four wings, which are usually 

 floury, and may be immaculate or spotted or patched. Antennae 

 of seven joints. Eyes reniform (or more seldom divided), the 

 anterior segment the smallest; two small simple ocelli be- 

 tween the eyes. Mouth-parts consisting of a conical or sub- 

 conical protruding rostrum, at the end of which are three 

 tubular suctorial setae, and beneath the rostrum is an elongated 

 subcylindrical free mentum ; the mouth and digestive organs 

 are present m both adult sexes. First two joints of the an- 

 tennge small and simple ; remaining joints long, slender, and 

 numerously ringed ; the last joint terminates in two minute 

 spines. Feet long and slender, none of the joints being much 

 thickened; tibia usually about twice as long as the tarsus; 

 tarsus two-jointed, ending with three claws, of which the me- 

 dian is small and spiny. Abdomen in both sexes bearing 

 dorsally on the last segment a more or less tubercular (honey- 

 dew) organ composed of an orifice, an operculum, and a 

 lingula ; the lingula usually concealed, sometimes projecting. 

 Genitalia terminal ; genitalia of female conical, more or less 

 acute, divided into two sections, between which is the ovi- 

 positor; genitalia of male forcipate, enclosing the penis. Wings 

 exhibiting in each only a single median vein with one basal 

 posterior branch; the wings are carried flat at rest. 



Pupse enclosed in more or less transparent chitinous cases 

 of elliptical form, convex above, flat beneath. Eudimentary 

 antennae, feet, and wings enclosed, and in many cases visible 

 through the case. Rostrum and setae protruded. Pupa-case 

 naked, or bearing hairs or spines, which may carry more or 

 less of dorsal wax or meal ; margin composed of adjacent 

 tubes, from the ends of which may be produced a fringe of 

 waxy threads, varying in length and in solidity ; this fringe is 

 sometimes replaced by a ring of wax more or less thick and 

 elevated ; sometimes the fringe is entirely absent. On the 

 abdominal dorsum is an (honeydew) organ similar to that of 

 the adult, but usually less tubercular ; the lingula may }n-c- 

 trude or be obsolete. 



Larvae elliptical, usually flat and thin ; sometimes enclosed 

 in chitinous cases, which are discarded on changing to the 

 pupal state. Organs in the earliest stage not usually recog- 

 nisable, but becoming faintly visible with the growth of the 

 insect. Dorsal abdominal organ as in the pupa. 



