SPECIES MISTAKEN FOR PARASITES OF ALETIA. 



115 



motli was not yet formed. The duration of the pupa state of the Chalcis 

 Avas found to be from eight to ten days in August. In issuing from the 



Aletia pupa it almost invariably eats a hole 

 through the dorsal part of the thorax.'*" 



The DEVOURiNa Tetrastichus {Tetrasii- 

 cliiis esimis Eiley).'*^ — The chrysalides of Aletia, 

 formed during the latter part of the season, 

 are frequently infested with this little parasite, 

 each chrysalis nourishing a number which eat 

 their way through the shell in the form of small 

 black flies. This parasite is quite generally 

 distributed, and has been bred in Texas, Ala- 

 bama, and Georgia. The larvae are pale, elon- 

 gate, egg-like maggots, and the flies issue all 



Fig. 42.— Chalcis ovata, female; ^^ ' , ' ... .■,-... 



hair-line showing natural size, through the autumn, duriug mild Winter wcathcr 

 "^^"^ ■ and (the later ones) in the spring. There exists 



a possibility that this insect is not a so-called primary parasite of Aletia, 

 but that it infests naturally one of the large ichneumonid parasites of the 

 Cotton Worm. This supposition is, however, contradicted by the fact 

 that Aletia pupae parasited by this chalcid are always found packed to 

 overflowing with the Tetrastichus, whereas were the latter simply para- 

 sitic upon Pimpla or Chalcis, they would in all probability be found only 

 in the abdomen of the Aletia pupa. 



This parasite has also been bred from the fall broods of the worm only, 

 which fact may be due to the possibility of its parasitism upon Fimpla 

 conquisitor, or from its being, during the summer months, parasitic upon 

 some larva other than the Cotton Worm. 



SPECIES THAT ARE EASILY MISTAKEN FOR PARASITES OF ALETIA. 



Hexaplasta zi&zAa*2 (Figs. 43 and 44). — In September, 1879, a num- 

 ber of minute parasites were sent us by Professor Comstock, with the 



statement that they had issued from 

 chrysalides of Aletia. The species 

 was undescribed, and as we could 

 place it in no known genus, we erected 

 the genus Didictyum, and described 

 the species as D. zigzag in the Amer- 

 ican Entomologist^ III, 52, and also in 

 the first edition of this Bulletin, p. 

 44. Later, however, we learned, 

 through the courtesy of Mr. W. H. 

 Patton, of Waterbury, Conn., that 

 Didictyum is synonymous with the 

 Cynipid genus Hexaplasta of Foer- 



riG. 43.— ffexapZasteziflrzaf/; showing female from ' t-ititi ry j. • j.\ 



-vbove, and male and female anteuiuE— natural stcr, aud published the lact lU the 

 size indicated in hair-line. (After Riley). . . -n , 7 • , ttt r^r^o / j. 



American Entomologist, III, 293 (note 

 12). We also there expressed the belief, based on careful observation, 



