PSYCHE 



THE FEMALE OF EUTERMES RIFPERTII. 



BY HERMANN AUGUST HAGEN, CAMBRIDGE, MASS. 



The ovarium of the imago. 



The dark colored, mature-winged 

 imago, taken out of the nest befor^ 

 swarming (therefore before copulation) 

 was dissected. The color of the ova. 

 rium is pale and whitish. Each ovarium 

 is connected within the ends of the meta- 

 thorax with the dorsal vessel by a very 

 fine filament. The end of the filament 

 measures only .003 mm. in thickness, 

 and in the middle between the insertion 

 and the sudden dilatation of the ovarium 

 the filament is .023 mm. in thickness. 

 Each stigma sends a very large bvmdle 

 of tracheae to the external part of the 

 ovarium. Where the first bundle reaches 

 the ovarivmi a rounded dilatation is to be 

 seen, and from here the ovarivmi in- 

 creases slightly. Nevertheless, its thick- 

 est part, just before the oviduct, though 

 containing some eggs in an advanced 

 stage of development, is only .512 mm. in 

 thickness. The internal half of the whole 

 length of the ovarium is somewhat paler 

 and consists apparently of the filaments 

 of the egg tubes, one running very near 

 to the other, without any twisting and all 

 so closely connected, that a separation 

 is impossible. I was not able to, observe 



in this internal part any tracheae. The 

 external part is visibly darker and pro- 

 vided with very numerous tracheae. The 

 bundles of the tracheae reach the ovarium 

 in a horizontal direction in the begin- 

 ning of the abdomen ; those that follow 

 go obliquely from behind forward to the 

 ovarium, and rise there from a single 

 main stem of .118 mm. in diameter, 

 while the two bundles in the beginning 

 of the abdomen rise from two or three 

 smaller main stems. Just before reach- 

 ing the ovarium, the main stem of the 

 tracheae is suddenly divided into very 

 numerous smaller branches, which enter 

 the ovarium, divide again like a braid 

 between the filaments and are curved 

 there to provide the interior of the ova- 

 rium. Some remain externally on the 

 superficies of the ovarium, and are 

 divided into very fine branches running 

 in an irregular, meandrous manner. 

 The finest I was able to measure, were 

 .003 mm. in thickness. Following the 

 last attached bundle, the ovarium is 

 pear-shaped, dilated, the egg tubes visi- 

 ble and dilated, and filled with a number 

 of eggs, the largest ones, a dozen or 

 rnore, of dark, amber color and of the 



