478 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvii. 



onoiiiic value. Orifice subcircular; operculum more than one-half the 

 lenoth of orifice, deeply emarginate on the distal end; ling-ula longer 

 than orifice, subcylindrical, either somewhat pointed or else enlarged 

 at the tip, usually protruded and dorsally recurved; both operculum and 

 lingula setose. Genitalia of female conical, in three parts, the middle 

 one of which is the ovipositor. (Fig. 44, Plate XXXIII.) Genitalia 

 of male forcipate, also in three parts, the outer two of which are the 

 valves or claspers, and inclose the penis. (Fig. 57, Plate XXXV.) 



PupsK inclosed in more or less transparent, chitinous cases, usually 

 elliptical in shape. Rudimentar}^ legs and antennae inclosed, but when 

 the case is sufficiently transparent they are often visible. Pupa-case 

 naked, or bearing hairs or spines; dorsum free from secretion, or it 

 may have a more or less copious white wax covering, which is fre- 

 quently arranged in definite patterns, and often of great beauty; 

 margins made up of adjacent lateral wax tubes, from the ends of 

 which may be produced a fringe of transparent wax rods, or asbesti- 

 form thi-eads of wax, more or less covered with fiocculent wax. On 

 the dorsum, in the last segment of the abdomen, is found the vasiform 

 orifice which is the most distinctive character in this family, and in 

 the immature stages forms the basis of classification. It is an open- 

 ing variously modified in shape, with a lid, the operculum, which is 

 hinged to the cephalic margin; this lid ranges in size from minute to 

 large; lying within the orifice beneath the operculum is the lingula, a 

 strap-shaped organ, also attached to the cephalic margin; in general 

 shape, cylindrical at base and more or less enlarged at the distal end; 

 in some specimens it is entirely obscured l)v the operculum, while in 

 others it is conspicuouslv long, even projecting beyond the orifice; 

 the distal portion is frequently protruded and dorsally recurved. The 

 operculum and the distal part of the lingula are usually setose, and the 

 latter, as a rule, bears two long apical hairs (fig. 80, Plate XXXI). 

 On the ventral surface of the case are four pairs of spiracles, a pair on 

 each of the thoracic segments, and a pair on the abdomen, lateral of 

 the vasiform orifice. In freshlv mounted specimens the tracheae are 

 often filled with air, and consequently may be easily traced (figs. 55, 

 56, Plate XXXV). 



Larvje thin and usually flat; elliptical in shape; early stages semi- 

 transparent and ranging in color from white to yellow; dorsum 

 naked, or with hairs or spines; with or without lateral fringe and 

 dorsal secretion. Vasiform orifice as in pupa?. In the beginning of 

 the first stage the larvt« are free and active, legs and antenna? func- 

 tional; after the first moult these organs are not usually recognizable 

 until a somewhat later stage (fig. 58, Plate XXXV). 



Eggs 3^ellow and ellipsoidal, with or without polygonal markings of 

 shell; attached b}^ a peduncle to leaf, usually laid in circular groups.'* 



« For a more detailed account of the characters of Aleyrodidse, see Maskell, Trans. 

 New Zealand Inst., 1895, p. 415. 



