142 
NEUROPTERA. 
timum temperature, plentiful food, abundant flies hatching out together, 
and a suitable food-supply for the young, on which the parent may lay 
eggs, the period is reduced to the least possible, the egg hatches quickly, 
the larva quickly lays up food, the transformation is quickly accomplish¬ 
ed and the flies quickly find mates. It will serve no useful purpose to 
attempt to summarise more closely than above, but we may indicate briefly 
the characteristics in this respect of some of the larger groups, with 
regard to Indian insects primarily, but where our knowledge fails, to the 
group as a whole. The known Cicadas are the longest, the known Dro- 
sophilides, Culicides and some other Diptera the shortest. Blattids ap¬ 
pear to be long, four years or less for some species. Maniidce are pro¬ 
bably at most two-brooded in the year, many probably one-brooded. 
The same is probably true of Phasmids ; Acridiids require one year, or 
have two, three or four broods yearly, probably more only in rare cases 
(such as Chrotogonus and Atractomorpha). Locustidce are probably one- 
brooded in most cases and nothing is known of Gryllids, though there is 
reason to believe that some are many brooded, most one-brooded. 
Most of the known aquatic Neuroptera seem to be two or more 
brooded, imagos appearing several times in the year and the period in 
Ephemeridce , for instance, is probably normally short enough to give 
several broods yearly. The larger Neuroptera Planipennia are apparent¬ 
ly one-brooded, but the predaceous Hemerobiides and Ckrysopides are 
many brooded. Predaceous land Neuroptera, like many other preda¬ 
ceous forms, seem to have the power of enduring long fasts and the life - 
history may be much prolonged accordingly. 
Tenthredinidce are many brooded so far as known, and the period 
for many parasitic Hymenoptera is very short, shorter than that of their 
hosts in many instances. Aculeata have short lives, several broods usual¬ 
ly being produced in a year, and here we have an instance where the com¬ 
pletion of sexual functions does not bring death , since workers have none ; 
their life is however not long, the worker being exhausted within a com¬ 
paratively short time (in the bee six weeks). A large number of Coleop- 
tera require a year for complete life and many emerge as imagines only 
at one season yearly. This does not apply to Coccinellidce , to some Bu- 
prestidce, to household and grain beetles, to some Chrysomelidce and 
Curculionidce (e.g., Apoderus , Hypera, Cionus). On the other hand, 
many Carabidce , Cicindelidce , Scarabceidce , the larger Elateridce and Bu~ 
prestidce, Cantharidce and many Curculionidce have a period of at 
least of one year; while some Cerambycidce, the large forms of Lucanidce 
and Scarabceidce , probably require more than one year. In Lepidoptera 
we have some which require but a month, and complete six to eight 
broods yearly, and those which require a year and emerge once only; 
but the majority have at least two and many, more than two broods. 
Our ignorance of Diptera is profound, but the order certainly includes 
some of the shortest lived and probably few really long-lived ones . Per¬ 
haps Diptera are summed up best by saying that the majority have short 
