habits of certain spexies of Eurijtomides. 323 



Isosoma orchidenriuii, Westw. (PL XITL, figs 1 & 4). 



Nigrum, modice elongatum, capite et thorace rude 

 punctatis, antennis maris longe pilosis, articulis inter- 

 mediis crassioribus singulo apice strangulate, articulis 

 2ndo brevi, annulo inter hunc et sequentem articulum, 

 4 proximis sensim minoribus, 7mo subovali, 8mo fere 

 prfecedenti sequali, ultimo 9no parvo subconico; foeminae 

 articulis 7 pone annulum fere fequalibus subovalibus, 8vo 

 prgecedenti parum majori, 9no longiori, articulo Imo 

 liujus sexus basi fulvo, maris nigro ; pedibus maris 

 geniculis tarsisque tibiisque anticis fere toto fulvis, 

 articulo ultimo tarsorum nigro : foeminae tibiis inter- 

 mediis etiam fulvis, Abdomine nitido glabro compresso, 

 maris ovali apice rotundato pedunculo longiori; foeminse 

 pedunculo breviori, apice abdominis acuto. Alls pallide 

 fumosis immaculatis iridescentibus. Long, corp, 4 — 5 

 mm. ; expans. alar. 6 — 7^ mm. 



Hah. In gemmis Cattleyise cujusdam Brasilianae. 



In April, 1881, I received from a correspondent 

 (Inquirer) several buds of a species of Cattleyia, a 

 Brazilian and Mexican genus of Orchids, which had been 

 injured by the larvae of a small Hymenopterous insect, 

 of which a figure is given in the accompanying Plate xiii. 

 Fig. 10 also represents one of the Cattleijia buds cut open 

 at the base, showing three of the larvae (' Gard. Chron.,' 

 30th April, 1881, p. 575). 



From another correspondent (E. C.) I also received 

 several Cattleijia buds which had holes bored in the 

 interior, within which I found several specimens of the 

 Isosoma orcJddearum of both sexes in the winged state 

 ('Gard. Chron.,' 22nd October, 1881, p. 542). This 

 discovery led to my publishing a short note " On the 

 Abnormal Economy in certain Species of the Euryto- 

 mides" in the ' Gard. Chron.,' 29th October, 1881, p. 567. 



Plate xiii., fig. 1, represents the male of/, orchidearum, 

 the separate outline fig. 3 representing the delicate 

 ceratotheca or pupal sheath of the flagellum of the 

 antenna, not exhibiting the slightest trace of the nodosity 

 of those organs in the imago state. 



Fig. 4 represents the female, with (fig. 6) the cerato- 

 theca of its antenna. 



Fig. 8 represents a portion of the shoot of the orchid- 

 aceous plant, communicated by Mr. Bateman, partially 

 opened, showing one large larva of a weevil and four 



