No. 34.] HEMIPTERA OF CONNECTICUT: ALEYRODIDAE. 335 



Wilson, H. F., and Vickery, R. A. 1918. A species List of the Aphididae 

 of the World and their Recorded Food Plants. Transactions of the 

 Wisconsin Academy of Sciences, Arts and Letters, vol. xix, pt. I. 



Witlaczil, E. 1882. Zur Anatomic der Aphiden, 1882. Ztschr. f. w. Zool., 

 38. 



Family ALEYRODIDAE. 

 By Wilton Everett Britton, Ph.D. 



The insects belonging to this family are small, 3 mm. or less in 

 length, wings and body opaque, our species whitish, more or less 

 mealy, the wings in some species marked with dark spots or bands ; 

 tarsi of two joints, nearly equal, a spine-like or pad-shaped process 

 (paronychium) between the claws. Pupa stage present in both 

 sexes. 



Egg, nymphs, pupae and adults are found on the under side of 

 the leaves of various plants, a few species being important pests. 

 The tropics furnish by far the greatest number of species, many 

 of which are carried on plants into northern greenhouses. 



Only about a dozen species are known to occur out of doors in 

 the northeastern United States. Formerly all of our species were 

 placed in the genus Aleyrodes but recently this genus has been 

 subdivided and Dr. A. L. Quaintance and Dr. A. C. Baker of the 

 Bureau of Entomology, Washington, D. C, who are leading 

 authorities in this group, have recently published a comprehensive 

 review of the family.* Free use has been made of their work 

 and their classification has been adopted in the preparation of this 

 paper. Explanation of structures is shown in Fig. 32. 



Key to Genera. 



1. Fore wing of adult without radiusi 2 



Fore wing of adult with radiusi present as a distinct vein 



Aleurochiton, p. 336 



2. Pupa case with dorsal disk not separated from the submarginal area 3 

 Pupa case with dorsal disk separated from submarginal area by a 



suture-like line or depression; submarginal papillae lacking; 

 dorsum without large mammiform pores; vasiform orifice 

 rounded or cordate, elevated and not surrounded by a lobed or pal- 

 mate area . .Tetraleurodes, p. 337 



3. Vasiform orifice subcordate with anterior margin straight; lingula 



projecting beyond operculum, and bearing a pair of spines; 

 thoracic tracheal folds not evident; wax secretion if present usu- 

 ally in the form of long glassy rods 4 



Vasiform orifice subcircular; operculum nearly filling orifice; 

 lingula not projecting; thoracic tracheal folds ending in a comb 

 of teeth ; wax secretion tufted and plume-like arising from minute 

 pores Aleuroplatus, p. 338 



4. Pupa case with a submarginal row of papilla-like pores; lingula 



lobed .....*.. .Trialeurodes, p. 339 



Pupa case without a submarginal row of papilla-like pores ; lingula 

 not lobed Aleyrodes, p. 344 



* Technical Series No. 27, Parts I and II, Bureau of Entomology, U. S. 

 Department of Agriculture. 



