GEORGE HENRY HORN. XVll 



Evolution' (Chicago, 1896), as evidence that variations of specific 

 characters "are of certain kinds or in certain directions." 



As early as 1868, in a brief communication,'^ "The importance 

 of large series of this [^Amphizoa'] and other genera was urged on all 

 who have collections, as the only means of arriving at a knowledge 

 as to what constitutes a species." And in his Revision of Lachnos- 

 terna''3p. 209, he remarks, "As it is never profitable to describe 

 isolated species in troublesome genera, it was better to accumulate as 

 large series as possible in order to determine the limits of variation, 

 and thereby fix the value of many described from uniques." Never- 

 theless, it is quite true that many of his specific descriptions are 

 based upon a single specimen. On the other hand, Prof. Smith's 

 subsequent studies on this very Lachnosteriia, published in Horn's 

 lifetime, showed that Horn had united, as one species, several forms 

 structurally distinct. 



His habitual refrain from generalizing was shown even in his 

 young manhood- for, referring to the discovery of a species of Paeu- 

 domorpha in California, he remarks " that it "adds another fact to 

 the already inexplicable law of distribution of genera in Australia, 

 South America and California." 



At the meeting of the Entomological Section January 10th, 1879, 

 " Dr. Horn exhibited two Lepidopterous insects from Costa Rica of 

 widely separated afiinities, showing between themselves a realty 

 wonderful mimicry, not only in color, but also in form ; so. close, 

 indeed, was the resemblance that either might have been placed 

 among a number of specimens of the other, and without a careful 

 glance, would not be thought distinct. The one was a Helicnnia, 

 the other a Callimorpha. The group to which the former belongs 

 is rarely or never attacked by birds, and the mimicry belongs to 

 the ' protective' class. In regard to matters of ' mimicry' so called. 

 Dr. Horn thought the idea had been and is pushed too far. Many 

 cases of this kind should be considered Nature's reproduction of an 

 idea, so to bpeak, which had been developed elsewhere, and that such 

 instances do occur among the myriads of insects is not very remark- 

 able. Instances of equally wonderful ' mimicry' could be cited 

 among Coleoptera where it is not protective or anything else than a 

 mere close resemblance, for example Amphizoa, from California, and 

 Nyctipetus, from South America." '^ 



He did not fail to perceive the importance of studying the earlv 

 stages of beetles, and at the meeting of the Entomological Society 



TRANS. AM. ENT. SOC. (3) MAY. 1898. 



