144 Annals Entomological Society of America [Vol. XIII, 



-summer, so we find the nymphal period both longer and later 

 and the adults extending into the fall. 



A striking adaptation to a special period in a plant's growth, 

 is shown in the life cycle of Micrutalis calva, the little shining 

 black seed-like tree-hopper. The nymphs are found between 

 the branches of the blossom head of the Ironweed, Vernonia. 

 This purple flower appears only in the fall, so that the single 

 generation of nymphs comes on over 70 days later than its 

 relative that lives in the tree. 



Later appearing nymphs usually come from overwintering 

 adults that feed for some time before laying eggs. The complete 

 "life cycle of this species is not known. What we do know cor- 

 responds with the life cycle of Publilia in which we know that 

 the adults hibernate and that there is a single generation on 

 thistles, sunflowers and other late growing CompositcB. 



The writer has never studied a double brooded tree hopper. 

 Funkhouser, a careful student of the family, has, however, pub- 

 lished the details of his observations on Vanduzea arcuata which 

 lives on the Black Locust. From the observed facts the writer 

 has been able to construct a complete life history chart showing 

 two generations, with the winter passed in the egg stage. 



It is to be regretted that after completing this fine series of 

 -observations that Prof. Funkhouser allowed himself to be led 

 astray by the example of that all-too-numerous band of dilet- 

 tante and superficial workers in Entomology whose chief indoor 

 sport has been the working out of life histories by the math- 

 ematical route. The only thing necessary for these scientific 

 wizards is to ascertain the time that it takes an egg to hatch and 

 a nymph to develop, add the two, and divide the length of the 

 season by this number. The quotient is not the number of 

 generations nor even the number of possible generations of the 

 insect that they fondly imagine it to be, but a mathematical 

 fiasco and a scientific absurdity, patent to anyone who will give 

 the matter serious thought. 



If the time of the stages used was a fair average of the season 

 •our short-cut investigator will probably find three or four 

 broods. If the minimum time found in the midsummer period 

 alone is used and our rapid calculator is optimistic about the 

 •spring and fall weather, as he is usually, then at least 5 or 6 

 .generations will be proclaimed. If our mathematical prodigy 

 "would only take the trouble to investigate the literature (which 



