Periodical Appearance of certain Insects. 24:7 
Art. X. On the Periodical Appearance of certain Insects. By 
J. H. Daviss, Esq., Lieut. R. M., late Curator of the Museum 
of the Portsmouth Philosophical Society. 
Sir, 
Tar certain insects occasionally appear very numerously, 
and are again for a period comparatively rare, ‘has been long 
noticed by entomologists, and some instances are so striking, 
as to excite the attention of the most incurious observers ; but 
J am not aware that any attempt has been made to ascertain 
whether the intervals are stated or irregular, or how far they 
are influenced by the temperature of the seasons. The observ- 
ance of these interesting facts may perhaps form a desirable 
feature in your proposed Perennial Calendar of Nature: in 
the mean time, the pr evalence of certain insects, as they came 
under my observation in this neighbourhood (Portsmouth) 
during a ‘few seasons past, may perhaps be worthy of note. 
1825.— apilio cardui, P ainted Lady Butterfly, is one of this 
tribe, mentioned as an occasional visitant. T'his year I found 
a field of red clover completely covered by them; since when 
they have been scarce. Papilio cardamines, Or ange ‘Tip, 
was also particularly numerous. ‘The genus Chrysomela was 
very plentiful : a long hedge near Milton was crowded with 
the C. aiicta, C. Mer shar and others. I have since visited 
the same spot without success. 
1826.— Papilio crateegata, Black-ribbed Butterfly, is rather 
a local insect. In the previous summer I met a scientific 
tourist from Suffolk, who informed me that he had _ visited 
Hants to procure this insect, which he understood was here 
plentiful : we searched for it several days to no purpose ; but 
this year they were more numerous than even the common 
Cabbage White, abounding in every field: since then very 
scarce. The Musca genus unusually plentiful. Great num- 
bers of Cerambyx violaceus were also taken. This year was 
marked by the prevalence of that pest to fruit trees, Phalae‘na 
Neustria, Lackey Moth. In the spring the boughs were 
covered with the webs of the larvee; and so plentiful was the 
moth in the autumn, that more than one hundred flew into my 
study window on one evening: they have not since appeared 
in such numbers. 
1827.— Papilio A’rgus, Argus Butterfly, studded the fields 
with its blue wings in unusual numbers. Hister quadru- 
maculatus, of which I had previously taken few specimens, 
now covered Southsea Common, so that many were crushed 
under foot at every step; with them was Carabus ceerulés- 
cens, in equal numbers: and between the two a deadly war 
