— 2 



or color may differ. The variatioDS of M- olivacea were alluded to, and though 

 he had separated two species on apparently excellent characters of maculation, 

 yet he fully expected that they would ultimately prove varieties or races of the 

 Bame species* 



Dr. Williston stated thai the result of Ins studies in Diptera had led him 

 tn hold views in accordance with those of Dr. Horn. He hud been much inter- 

 ested in the results, recently published, reached by Dr. Horn and Mr. Smith in 

 reference to the value of sexual characters. In the Diptera the range of color 

 variation was very wide. Specimens, of the same species in his cabinet ranged 

 from clear yellow to deep black. They were undoubtedly the same species lie- 

 cause he had every intergrade in his series; yet some writers would be apt to 

 make four of five distinct species out of them. Species should be very cautiously 

 described on color characters alone, no matter how well marked they appeared 

 to be. The time for indiscriminate description had passed, and comparative 

 Entomology must now be specially studied. 



Dr. Horn then spoke as to genera. The variation of species w r as almost univer- 

 sally admitted, and by the theory of evolution was explained. But genera varied 

 also— they so gradually intergraded that there were but very indistinct lines of de- 

 marcation. However disinclined workers might be to affirm their belief in evolu- 

 tion, all the best work done was wittingly or unwittingly based on it. Keeping 

 that as a guide permanent arrangement of groups of genera and species can be 

 made. An illustration was drawn from the Melokla; in the highest type of which 

 the claws were distinctly bifid, the parts equal, the upper portion pectinated. 

 These varied gradually to the perfectly simple, single claw. Jiy reasoning from 

 the theory of evolution he sometime since predicted the occurrence of two further 

 genera that would fill gaps left in the series by the then known forms. One of 

 these predicted genera has been since discovered. He confidently expected the 

 occurence of the other. Mr. Smith spoke as to the generic divisions of the Lepi- 

 doptera. The hairy eyed genera of the Noctuidae especially afford an instance. 

 Mamestra, Tceniocampa and Xylomiges though widely separated in the lists yet 

 ran so close that it was next to impossible to draw a distinct line between them. 

 Species occur which might with almost ecpial propriety be referred to either 

 genus. 



Mr. Hulst spoke on this subject. In his opinion nature must be taken as 

 we find it, and whatever our opinion on the theory of evolution, in practice it 

 would be found that nature had certain gaps that could be utilized in systematic 

 work. The chain was nowhere complete, and with the amount of material that 

 falls to the lot of the ordinary collector no trouble is experienced. He alluded to 

 the inconstancies of characters used in separating families, in the Geornetridce, 

 The venation, which forms the basis for the highest divisions in Lepidoptera, 

 often in the Geometrida varies essentially in one and the same species. 



The remainder of the evening was spent in informal discussion, during 

 which Dr. Horn illustrated three varieties of rf $ found in Oryptdbium. Nearly 

 every species has these varieties, one of which. Dr. Born calls a complete ., 

 another an incomplete tf, the third an imperfect A paper now in press will 



completely illustrate these forms. 



The Treasurer reported the amount of the Publication fund $150 as fol- 

 lows: Life membership fees from E. L. Graf, John l'>. Smith and Prof. C. V. 

 Riley, each $50 = $150. 



