Maskell. — On x\leurodidae. 445 



domen ending in an organ formed like a forceps " (p. 378). 

 x\nd in all the species which I have seen this feature is quite 

 constant, as shown in the figures attached to this paper. I 

 cannot therefore include this amongst the generic characters 

 of Alciirodicus. 



In a note to the same diagnosis {loc. cit., p. 82) Mr. Doug- 

 las says further that Aleurodicus differs from Aleiirodes "in 

 the characteristics of the larva." But nothing is given in the 

 description of the text which is any more than a specific 

 difference, and I cannot see how the larva is to be employed 

 for generic purposes. 



The doubly-branched nervure is, however, a sufficient 

 character for separation. 



1. Aleurodicus anonae, Douglas and Morgan. Ent. Mo. 

 Mag., 1892, vol. xxviii., p. 32. 



2. Aleurodicus asarumis, Shinier. Trans. Amer. Entom. 

 Soc, vol. i., p. 281. 



This species is here placed in the genus Aleurodicus on the 

 authority of Messrs. Eiley and Howard, Insect Life, 1893, 

 p. 219. 



3. Aleurodicus cocois, Curtis. Aleurodes cocois, Curtis, 

 Gard. Chron., 1816, p. 284; Signoret, Ann. de la Soc. 

 Ent. de France, 1867-68, p. 398 ; Aleurodicus, Douglas 

 and Morgan, Ent. Mo. Mag., 1892, p. 32; Eiley and 

 Howard, Insect Life, 1893, p. 314. 



4. Aleurodicus ornatus, Cockerell. Ent. Mo. Mag., 1893, 

 p. 105. 



INDEX TO PLATES XXIV.-XXXV. 

 Plate XXIV.— 1. 



Tyyes of details; greatly magnified. 



a. Type of adult Aleurodes. 



b. Head of a;lult viewed from above. 



c. Head of adult viewed from beneath, showing rostrum and mentum. 



d. Head of adult viewed sideways, showing rostrum and mentum. 



e. Antenna of adult. 

 /. Eye of adult. 



g. Foot of adult. 



h. Last joint of tarsus and claws. 



Plate XXIV.— 2. 

 Types of details; greatly magnified. 



a. Type of wings of Aletirodes. 



b. Type of forewing of Aleurodicus. 



c. d, e, /, types of marginal serrations cf wings: c, A. asplenii ; d, A. 



piperis ; e, A. asparagi ; /, A. T-signata. 



