egg production. After extirpation or other ways of elimination of the corpus 

 allatum, the oocytes will grow to the size when yolk should normally be 

 deposited, and then degenerate. After implantation of a corpus allatum into 

 a female lacking this organ normal yolk-containing eggs are produced. 



In a normally fed Oncopeltus female, the corpus allatum increases in volume 

 after emergence and may reach a considerable size. In male individuals the 

 organ stays much smaller, but in both sexes the organ shows considerable 

 individual variation in volume. 



This normal growth and development of the corpus allatum, is in Oncopeltus 

 strongly influenced by the nutritional state of the specimen. In females, 

 starved or fed on glucose from emergence, the corpus allatum remains much 

 smaller than the organ from an equally old, normally fed female. On the whole, 

 the \^olume of the organ depends on the quantity and the quality of the food 

 in the same way as the egg yield does. A comparable dependency of the morpho- 

 logy and function of the corpus allatum on the nutritional state has been ob- 

 serл^ed also in several other insect species. 



The fact that in Oncopeltus both egg output and the corpus allatum react 

 to changes in the nutritional state of the animal, may be the result of a chain 

 of events: the nutritional state influencing the corpus allatum and this again 

 regulating the activities of the ovaries. 



Let's take a clearcut example: a female starved after emergence which, 

 as we know, will normally not produce eggs and has a small corpus allatum. 

 If we implant a corpus allatum from another adult indi\idual into such star- 

 ving female, eggs are produced even if the female is given no food except the 

 usual water. If fertilized, such eggs may develope to normal individuals. This 

 shows that the effect of starvation on egg production in this case is mediated 

 through the corpus allatum. 



Similarly, if we implant a corpus allatum into a female fed on glucose, eggs 

 are also produced. Here, as in a starved individual, the female at the time 

 of emergence, has enough materials carried over from the nymphal period 

 to be able to produce a small number of eggs, provided the hormonal require- 

 ments are satisfied. Normally in females which are starved of fed on glucose, 

 the corpus allatum does, however, not reach the potency necessary for egg 

 production. 



This induced production of eggs in the glucose-female finally ceases, although 

 the specimen may survive. This may at least have two explanations: either 

 the implanted corpus allatum gradually looses its potency, or the stores 

 of materials necessary for yolk formation are depleted. Probably the last 

 explanation is the right one. If we, namely, at the end of the period of the induc- 

 ed egg laying, take the implanted corpus allatum out again and re-implant 

 it into another пелу1у emerged female, this пелу individual, thanks to the 



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