Dr. Fr. Meinert on the Ugimyia- Larva. Ill 



was found three or four times still occupying such a sac 

 corresponding to the lump. 



In connexion with what is here stated, I shall call attention 

 to the fact that those TachinaA&rvse that feed parasitic-ally on 

 insect-imagines* in a similar way occupy a sac formed by 

 the trachea of the host (conf. Cholodkowsky, Zool. Anzeig. 

 1884, p. 316), a fact which I have had the opportunity of 

 ascertaining myself when examining the maggot of Tachina 

 pacta infesting a Carahus kortensis. 



When therefore Mr. Sasaki says that the maggot of 

 the Ugimyia occupies a cup, I agree with him to some 

 extent, although I deem it more appropriate to style the 

 " cup " a sac. But, in opposition to his views, I am of 

 opinion that the maggot only for a time occupies that place 

 and that it leaves it, sooner or later, in order to force its way 

 into the central part of the body of the silkworm or of the 

 pupa. At what time the maggot emigrates from its sac I 

 cannot say precisely ; 1 have had too i'ew silkworms at my 

 disposal. But this I can maintain, that the maggot is 

 very seldom found in the trachea of the pupa, and that it is 

 often very young when it leaves the sac, viz. in its second 

 larva-stage, the length of such emigrated maggots being some- 

 times only from 3*8 to 4 millim. Perhaps this migration may 

 be influenced by the moultingsor the pupation of the maggot. 



Having at my disposal a very great number of maggots, 

 of every length from 3*8 to 14 millim., I had a fine oppor- 

 tunity for studying the evolution of the spiracle-plates. I 

 have not seen the first larval stadium of the Ugimyia-msiggot, 

 viz. from its leaving the egg until its locating itself in the 

 corpus adiposum of the silkworm, but I had before me the 

 three following stages. In the second stadium the spiracle- 

 plates exhibit only two short, broad, thin-skinned areas 

 (" fissures "), while in the third stadium these areas are three 

 in number, a little longer, somewhat narrower, and already 

 of a rather angular shape. In the fourth (or last) stadium 

 their number continues three ; but they have become long 

 and comparatively narrow, with curved outlines. In all 

 stages I found that the spiracle-plates were closed, the so- 

 called " fissures " were no fissures, and the respiration takes 

 place through the thin-skinned areas of the spiracle-plates. 

 This remarkable circumstance, however, perfectly agrees 

 with the fact that the Uyi?nyia-maggots are found imbedded 



* With other Tachina-la,r\se, which force their way into the body 

 of their host through its skin, the hypodermis of this skin forms the 

 sac (ejr, Auth. Entom. Tidsskr. 1866, p. 191). 



