72 THE CANADIAN ENTOMOLOGIST. 



These results, as published, are marred by contradictory statements 

 in reference to one of the experiments. Briefly, the result of the second 

 part of Exper. No. H 409/41 1 should be, and is stated to be, the same as 

 the result of Exper. No. H 410, but the result described on p. 295 and 

 figured in Plate III is anything but that of H 410 ! The article being a 

 preliminary one, many of the details are very meagre. This is especially 

 the case with regard to the duration of the peculiar conditions and with 

 regard to the conditions (normal ?) under which the subsequent generations 

 were bred. The title of the article calls for peculiar (varying) conditions 

 at fertilization. In most cases the author states that the species were 

 crossed or mated under the conditions, but in one case he states that the 

 eggs developed under the conditions. This permits of the results being in 

 part purely ontogenetic. Some of the results appear to indicate this. 

 However, the interaction between the two germ plasms might be assumed 

 to continue throughout the ontogeny. In that case a longer duration of 

 the stimuli would be advisable. 



In the previous experiments the different kinds of progeny were iso- 

 lated and bred separately (Experiments in Analysis). In another series of 

 experiments the species were permitted to hybridize freely under diverse 

 natural conditions, and these are called Experiments in Synthesis. Crossing 

 between L. iifidecimlineata and L. sigiiaticoUis at Cuernavaca resulted 

 finally in the complete disappearance of the former species. The same 

 cross at Paraiso resulted in the disappearance of L. signaticollis. 



In experiments with Z. decemli?ieata^L. oblongata and L. vmltitceniata, 

 conducted at four different places, a single type, which bred true, was 

 obtained in each case, but of the types obtained no two were alike. The 

 type at Balsas was a complex of the three species used. The type at 

 Escamela was an intermediate between Z. decemlineata and Z. oblongata. 

 The type at Tucson was a variable one, with the characters oi decemlineata 

 dominant. The type at Chicago appeared to be pure decemlineata. Subse- 

 quent cultures of these types (with the exception of the last) gave sporadic 

 variants (2-3%), which were reappearances of ''characters or combina- 

 tions thereof that went into the cross." Tower compares these with De 

 Vries' (Enothera mutants, and states that they behave in a similar fashion. 

 The author maintains that the variable outcome of these crossings under 

 natural conditions is the result, not of any process of natural selection, but 

 of some process of hybridization, which is influenced by the external con- 

 ditions. He states that this view is fully borne out by experiments in 

 which the selective factor was eliminated. — [A. G. Huntsman, Biological 

 Dept., University of Toronto. 



Mailed February loth, 191 1. 



