146 



was similarly swollen and contained another specimen of the insect. 

 Dr. Rose however was more fortunate, and after some search found a 

 single uninfested ovary, from which he was able to count the ovules 

 and thus to identify the plant. 





Fig. 20. Tanaostigma eoursetice .- a, ovary of Coursetia mexicana with the Tanaostigma jast issuing; 

 6, adult male — enlarged; c, male antenna; d, female antenna; e, veins of fore wing ; /, tip of middle 

 tibia and tarsus — still more enlarged (original). 



The specimens of the insect which had issued and were found in the 

 papers which contained the plants were badly broken, and it was im- 

 possible to extract perfect specimens from the swellings, but from such 

 as could be found it was at once evident that the insect was a very ex- 

 traordinary Encyrtid, the large and undivided mesopleura, five-jointed 

 tarsi, and the large mesotibial spur conclusively placing it in this sub- 

 family. 



Now, all the species of the Encyrtinse are parasitic so far as their 

 habits are known, and consequently the most careful examination was 

 made to decide whether some other insect had previously occupied the 

 swellings. The cavities were uniform, with no apparent opening, and 

 not a trace could be found, even upon microscopic examination, of any 

 insect other than the Encyrtid. The pupal exuvium of this last was 

 found, together with the characteristic little mass of excremental pellets 

 discharged just before pupation, but nothing else. It is conceivable 

 that the parasitic larva might have devoured its host *'hide and hoof," 

 but hardly conceivable that it should have eaten its excrement, yet of 

 this not a trace was to be found.* 



* Had this excrement been found, there Avould have been no difficulty in distin- 

 guishing it, as chalcidid larvae void no faeces in the course of their growth, but only 

 at the moment of transformation, when it invariably, so far as I have observed, takes 

 the form of a few (6-12) rather large pellets, grouped together, and of a grayish color. 



