ORGANS OF GENERATION. 221 



which, however, probably still consists of two divisions. From the two 

 hemispheres two delicate canals originate, which, after many con- 

 volutions, unite into a thicker but frequently twisted duct ; closely in 

 front of this point of union there hangs attached to the sperm duct a 

 simple, long, twisted vessel, the gluten gland. The development of the 

 female organs displays itself most conspicuously in the enlargement of 

 the ovaries. They increase at the expense of the egg canal, which by 

 degrees disappears, whereas the egg bags become continually longer, and 

 twist themselves up spirally from the apex. The point of union of the 

 very short oviducts distends, and sends off on one side a pointed bag, 

 the spermatheca; opposite this a smaller vesicle is formed with a longer, 

 vascular, much twisted appendage: farther below, near the vagina, 

 there hang also vascular, long, and much convoluted gluten glands. 

 Both distend prior to their emptying themselves, and perforate the 

 vagina at one spot close to each other. 



This is an abbreviation of the description of all the changes made 

 during the pupa state. In the caterpillar there were simple bodies 

 with simple delicate canals, these pass over unchanged in form into the 

 pupa, and undergo by degrees changes the results of which are the lastly 

 completed structure which we have here briefly indicated. 



It is to be regretted that similar observations have not been made in 

 several insects, and although they would probably present the same 

 results, many attractive details worthy of observation might be pro- 

 duced. This refers particularly to insects with an imperfect metamor- 

 phosis. We may ask does the transformation of the sexual organs take 

 the same course, and the bodies present at the birth of the larva merely 

 enlarge, and only when the pupa displays the rudiments of wings 

 undergo a general change of form ? If we refer to the development 

 of the intestinal canal, which has, from the commencement, its perfect 

 form, we might feel inclined to adopt the same view of the sexual 

 organs : we must confess that this view appears the most natural, 

 because in insects with an imperfect metamorphosis the pupa state 

 appears to be of infinitely less importance, and that consequently the 

 changes in structure cannot be so great as there where the pupa sleep 

 steps in so abruptly between the preceding and succeeding active 

 periods. And may not possibly the lesser degree of importance which 

 the pupa state possesses in insects with an imperfect metamorphosis be 

 the consequence of their smaller change in the form and structure of 

 their organs ? Could not, therefore, as the change of the internal organs 



