400 fVilliam Morton Wheeler 



It will be noticed that the preceding experiments were per- 

 formed only on holometabolic insects of the order Lepidoptera. 

 As such experiments on ametabolic insects might be expected to 

 yield different results, it is interesting to record that Regen ('09, 

 '10) has recently succeeded in castrating crickets (Gr}/lluscampes- 

 tris L). In his first paper he gives us little more than an orienta- 

 tion experiment performed for the sake of determining whether 

 the insects would survive the operation, but his second contribu- 

 tion brings ampler and more satisfactory data. In order to perform 

 the operation he narcotized the crickets with CO.,. The testes 

 were removed from 40 males (20 in the second last and 20 in the 

 last larval instar), and the ovaries were removed from 10 females 

 in the last instar. These 50 individuals were released in the open 

 field and each returned to the burrow which it is in the, habit of 

 occupying throughout its larval life. The operated individuals 

 were marked by cutting off portions of their wings, and near 

 their burrows stakes were placed with records of the necessary 

 data. After the crickets had reached maturity Regen recovered 9 

 males that had been castrated in the second last, 13 of those cas- 

 trated in the last larval instar, and 6 females. The insects were 

 left in their burrows. Ten days later he found that the crickets 

 had changed burrows and there was a tendency for them to as- 

 sociate in pairs, each consisting of a male and female occupying 

 a hole in common. Several individuals had migrated to other 

 parts of the meadow in which Regen experimented, but he suc- 

 ceeded in capturing and placing in a terrarium 10 males (4 castrated 

 in the second last and 6 in the last larval instar) and one female 

 On these specimens he made the following observations: 



"i. Nine imaginal males, part of which had been castrated 

 during the last and part during the second last larval instar, 

 chirped throughout the remainder of their lives in as lively and 

 shrill a manner as normal males. Only one of the males, which 

 had been castrated in the last larval instar, chirped feebly and at 

 rare intervals. 



"2. The behavior of the castrated males towards the females 

 was the same as that of normal individuals. They enticed the 

 females with theirshrillstridulation and when a female approached. 



