352 



The Journal of Heredity 



A non-disjunctional division in any 

 of the first few blastomeres will neces- 

 sarily result in the segregation of the 

 sex factors (producing male and fe- 

 male), provided the cell in which it oc- 

 curs has not reached the point beyond 

 which it becomes the progenitor of a 

 single embryo. If a blastomere has once 

 passed beyond this point in its develop- 

 ment, a non-disjunctional division in 

 any of its descendants should result in 

 the formation of a gynandromorph or 

 mosaic, as several writers have inter- 

 preted the origin ofgynandromorphsfor 

 the monembryonic egg. Evidence that 

 gynandromorphs are produced in poly- 

 embryonic parasites is furnished by two 

 cases which have come under my ob- 

 servation. In 1917, while studying a 

 brood of Paracopidosomopsis, I found 

 an individual in which one-half of the 

 abdomen is male and the other half fe- 

 male. This spring I found a specimen 

 in Platygastcr which is clearly a gynan- 

 dromorph. Sexual dimorphism in this 

 species is very indistinct. The only 

 clear mark of distinction is the anten- 

 nae, which are somewhat stouter in the 

 female than in the male, and, further- 



more, the fourth antennal joint ir the 

 male is enlarged. The specimen in 

 question has a male antenna on the left 

 side of the head, and a female antenna 

 on the right. 



The final solution of the question 

 concerning the origin of mixed broods 

 must be found through cytological 

 studies. However, one may attempt 

 to interpret the data presented in this 

 paper, the facts at any rate are per- 

 fectly clear and can be verified by any- 

 one who will make a careful study of 

 these insects. 



REFERENCES 



Bridges. Calvin B. Genetics, 1. pp. 1 - 52, 

 107-163, 1916. 



BuGNioN, E. Recueil Zool. Suisse, V, pp. 

 435-534. 1891. 



Marchal, p. Arch, de Zool. Exper, et 

 Gen.. II, pp. 257-335, 1904. 



Patterson, J. T. 1915, Biol. Bull., xxix, 

 pp. 333-373: 1917a, Biol. Bull., xxxii. pp. 

 291-305; 1917b. Biol. Bull., xxxiii, pp. 57-66; 

 1918, Biol. Bull., XXV. pp. 362-376. 



Patterson, J. T., and Porter. Lelia T. 

 Biol. Bull., xxxiii, pp. 38-50. 1917. 



SiLVESTRi. F. Ann. d. Regia Scula Super- 

 iore de Agricoltura di Portici. vi, pp. 1-51, 

 1906. 



Estimating Intelligence 



There is a general belief that it is a 

 relatively easy problem to estimate a 

 person's intelligence by looking at 

 him; and teachers, physicians and em- 

 ployers are often compelled to make 

 judgments as to the intelligence of a 

 given person with no more data than 

 can be obtained from a rapid survey of 

 his appearance; hence such phrases as 

 "he looks bright" or "he looks stupid." 

 Even in the law courts rough estimations 

 of intelligence are sometimes required. 

 In the Psychological Review (Vol. xxv, 

 No. 4) Mr. R. Pinter gives the results 

 of an investigation he made for the 

 purpose of testing the trustworthiness 

 of these judgments. The author chose 

 twelve photographs of children varying 

 in intelligence from proved feeble-mind- 

 edness to unusually great ability, and 

 asked groups of people to arrange the 

 photographs in order of merit for in- 

 telligence. His groups consisted of 



physicians, psychologists, teachers and 

 miscellaneous people. He found that 

 the group of psychologists was^the 

 most nearly correct, but that on the 

 judgment of no one group or of no one 

 person could any reliance be placed. 

 Several observers were consciously in- 

 fluenced by children of their acquaint- 

 ance whom a photograph happened to 

 resemble, and irrelevant trivialities quite 

 frequently biased the observer's judg- 

 ment. The author concludes that, al- 

 though perhaps a living person would 

 be easier to judge than a photograph, 

 nevertheless these haphazard judgments 

 are too untrustworthy to be of prac- 

 tical value; and that, whether the 

 observer be a teacher, physician, or 

 employer, it would be better to use 

 objective standards, and he recom- 

 mends that the use of mental tests 

 should be considerably extended. — 

 Nature. 



