Insects. 



6311 



and have never found one so inclined. Does this not again prove the two species, hy 

 the diflference of habitat of the larva ? I should much like to see a larva of P. Agestis 

 feeding on the Helianlhemum : who has ever found one? — H, J, Harding; 1, York 

 Street, Church Street, Shoreditch, 



[I agree with Mr. Harding that the fact of an insect settling on the blossoms of a 

 plant prove nothing as to the food of the larva : Sphinx Conv(»lvuli obtained its name 

 from the propensity of the imago to suck the honey of tubular flowers, but the conclu- 

 sion was a most rash one, and has led hundreds to seek the larvae among the leaves of 

 the bindweed. — JEJ. Newman.^ 



Double-btvodedness of the NotodontidcB, — The observations of Mr. Newman and 

 Mr. Boyd (Zool. 6281, 6283) on my paper on the *' Double-broodedness of the Noto- 

 dontidae " (Zool. 6248) appear to have been written under an entire misapprehension. 

 It is evident that both these gentlemen have the impression that the experiments with 

 Pterostoma palpina and Notodonta dictaea commenced in May, 1858, and terminated 

 with the larva in August of the same year. If I am correct in this supposition, they 

 are in error on both points; they have overlooked the fact that the communication 

 alluded to is a continuation of one published in the ' Zoologist ' (Zool. 5826). These 

 experiments commenced in August, 1857, with larva, and concluded in August, 1858, 

 with the ova, embracing a period of twelve months, and carrying both insects through 

 two entire cycles of life. I further mentioned, " almost parenthetically," that I had 

 commenced a third cycle, — that is, that I had larvae again feeding ; this latter obser- 

 vation, however, was only made to show that the last slate of the second cycle was 

 complete, — namely, that the eggs had proved fertile, — but beyond this I attached no 

 value to it whatever; these larvae formed no part of my experiments, the two cycles 

 were complete without them. Mr. Newman introduces Acherontia Atropos as an insect 

 which he says I should consider double-brooded ; on the contrary, this insect is entirely 

 single-brooded, according to the rule laid down by Mr. Newman himself, and with 

 which I fully agree : with Atropos no one of the four states occurs more than once in 

 the twelve months; indeed, necessarily, if one state occurs more than once all must: 

 it is true that individuals of this insect appear in autumn, the remainder in spring, but 

 it is only an irregular, prolonged development from the same set, — namely the autumn- 

 formed pupae. Will Mr. Newman say from which of my papers he gathered that the 

 divided or prolonged appearance of imago from the same set of pupae was considered 

 by me as evidence of double-broodedness ? Mr. Newman further says that the " state 

 of pupa (of A, Atropos) occurs twice." Now this may be said of every insect whose 

 pupa continues in that state from autumn till spring, and although it may thus be 

 found at two periods of a calendar year, it is only formed once in the four seasons, or 

 twelve months. This insect has only one cycle of life in a natural year : the appear- 

 ance of the imago in autumn is premature, and the individuals barren, dozens have 

 been opened in this town during this autumn proving this fact. Mr. Newman again 

 says *' But even supposing the two cycles of existence were completed by a Notodonta 

 in 1858'* (meaning, I suppose, twelve months) "still the temperature of the past 

 season having been abnormal the rapid progress of insect transformation may have 

 been abnormal also." I hope this is the dernier resort of dying doubt ; he appears to 

 forget that my experiments with N. ziczac, which produced the same results as those 

 with N. dictaea and P. palpina, were carried on during the years 1856 and 1857. 

 Mr. Boyd says, "I hope Mr. Gascoyne will publish the results of his experiments 

 when the cycle is complete/' I have before shown that the double cycle was com- 



