of the Mole-aicket. 425 



orange-red colour, proceeds to the ocellus or stemma of the 

 corresponding side. 



The upper surface of the brain is covered by a mass of soft 

 substance somewhat resembling loose fat. 



The sexual organs of the female* . — These organs consist of 

 two ovaries, which occupy a considerable portion of the upper 

 part of the abdomen, and terminate by a narrow duct in a 

 common cavity or uterus, which opens externally under the 

 posterior edge of the last segment but one of the ventral sur- 

 face of the abdomen. Behind the uterus is an oblong white 

 body, which originating from a. cid-de-sac, and then doubling 

 on itself in the form of a slender tube, terminates in the uterus. 

 The contents of this body resemble a thin white paste. The 

 ovaries are irregularly pear-shaped, and consist of a transpa- 

 rent membrane irregularly convoluted, through which the 

 ova, enveloped in a gelatinous medium, are easily distinguish- 

 ed. In the same ovary the ova are frequently of different sizes 

 and colours ; those which are the largest, and which I sup- 

 pose to be impregnated, are of a brownish yellow colour: they 

 resist a considerable degree of force before they burst, and the 

 contents when pressed out melt as it were into a soft jelly, 

 leaving a tough membrane which enveloped them. The small- 

 er ova are of various sizes and of nearly a white colour, and 

 of a much more slender and compressed form than those 

 which I have supposed to be impregnated. This difference in 

 the degree of maturation corresponds with a fact stated by 

 Riisel, that the mole-cricket does not deposit all the eggs 

 of the season at one time. In a few instances I found two 

 or three ova which had entered the narrowest part of the 

 duct and were very near the uterus ; and from the appearance 

 of these, which may fairly be supposed to be, if not impreg- 

 nated, at least in a state fit for impregnation, I have ventured 

 to derive the character of the impregnated ovum. 



The sexual organs of the male\. — I had dissected several 

 male gryllotalpae before I was fortunate enough to meet w-ith 

 the sexual organs fully developed ; and while I had as yet met 

 with only one animal bearing the character of full develope- 

 ment, I was not certain whether I judged rightly of the natu- 

 ral state of those parts, or whether their uncommon degree 

 of enlargement were not the effect of disease — the dispropor- 

 tion in size between the state in which they had hitherto occur- 

 red, and that to which I now allude is so enormous. However, 

 subsequent dissections presenting the same phsenomena, I have 

 no scruple in considering them as indicating full developement. 



• Vide Plate III. fig. 13. f Ibid. fip;. 14. 



Vol. GO. No. 332. /)^c, 182.5. 3H The 



