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SCIEHSE 



[Vol. IV., No. 99. 



season, while others appear quite punctually, re- 

 gardless of the season. In the same locality the 

 peach will blossom one year in February, another 

 not till May; and there is similar variation in the 

 first appearance of spring insects. The irregularity 

 lessens, however, as the growing season advances. 

 July is more uniform than April. From Boston to 

 Enterprise, Fla., one may travel in a couple of days 

 in January from ice-bound midwinter to summer 

 temperature, and, with the progress southward, 

 activity in both plant and insect life increases. In 

 a country so vast that it represents sub-boreal and 

 sub-tropical temperatures at one and the same time, 

 it were eminently improper to speak of the ap- 

 pearance of an insect without specifying the lati- 

 tude. The midwinter difference between Maine 

 and Florida, however, is not the difference between 

 dead of winter, and height of summer ; because there 

 is, even in the subtropical sections, a winter or 

 hibernating period when insect-life is comparatively 

 at a stand-still, or dormant. 



For calendar purposes the country may be di- 

 vided into northern, middle, and southern ; and, 

 where not otherwise stated, the following index to 

 the first appearance of some of our more conspicu- 

 ous insects will have reference to some middle 

 latitude. St. Louis is a very good point, being 

 central between the Atlantic and the Rocky Moun- 

 tains, our northern boundary and the Gulf; while 

 Washington is another, lying well between our 

 northernmost and southernmost borders. Be- 

 tween the Gulf and Lake Superior there is a dif- 

 ference in earliness of spring forms of nearly two 

 months, or of four to five days with each degree of 

 latitude, as the history of the Rocky-Mountain 

 locust (Caloptenus spretus) and of the army-worm 

 (Leucania unipuncta) shows. This difference, as 

 already indicated, diminishes for summer forms. 

 Development quickens in adaptation to the shorter 

 northern season ; and a widely distributed species, 

 that does not mature till August in Missouri, or 

 even Texas, may appear but a few days later in 

 Minnesota. 



January. — Hushed in a frosty cradle, as most 

 lower life is at this season, the snow-fleas (genus 

 Podura) — little, black, springing creatures not more 

 than one-twentieth of an inch in length — may never- 

 theless be seen during a mild spell, abounding on 

 the snow, even in the more northern states. To 

 the southward, whenever the temperature is above 

 freezing-point, the farmer will start from his corn- 

 shocks various hibernating bugs, as the chinch-bug 

 (Blissus leucopterus) and the tarnished plant-bug 



(Lygus lineolaris); while the housekeeper may be 

 alarmed by the buzzing of the paper-wasps (genus 

 Polistes), and particularly Polistes metricus and P. 

 annularis. Still farther south many butterflies, es- 

 pecially the yellows (genus Colias) and the whites 

 (genus Pieris), so common everywhere later in the 

 season, may be observed. 



February. — In average or normal years the in- 

 sect-life of this month resembles that of the pre- 

 ceding. On mild days swarms of small gnats 

 (Chironomidae) dance in the air near still waters, 

 while near larger streams small sombre-colored Neu- 

 roptera (Perlidae) will often fly. The wingless 

 female of the spring canker-worm moth (Paleacrita 

 vernata) ascends the trunks of apple and elm trees, 

 while the male, with ample wings, flits about her. 

 In the extreme north the remarkable wingless and 

 spider-like dipteron (Chionea valga)and the equally 

 remarkable neuropteron (Boreus nivoriundus), also 

 wingless in the female sex, may be seen upon the 

 snow; while in the south our heaviest-bodied but- 

 terfly (Megathymus yuccae) and our most graceful 

 species (Heliconia charitonia) are conspicuous, — 

 the one darting swiftly among the yuccas, the other 

 slowly sailing through the dense underbrush of the 

 shady hammocks. 



March. — Insect activity now rapidly increases. 

 With the thawing of the ice 'in ponds and ditches, 

 the water-beetles (Dytiscidae) appear, while in the 

 woods many species of ants (Formica) make their 

 way from their subterranean abodes. Many pine- 

 boring beetles (Buprestidae and Scolytidae) are 

 seen, and a small dung-beetle (Aphodius inquinatus) 

 flies in countless numbers. The velvety brown 

 larva of Telephorus will follow the melting snow, 

 the brown and black hedge-hog caterpillar (Arctia 

 isabella) will scamper across a sun-warmed path, 

 and the dipterous Bibio larvae will be found in 

 masses under decaying leaves in the garden. Of 

 butterflies, the mourning-cloak (Vanessa antiopa), 

 with its beautiful purple-brown and cream-margined 

 wings, somewhat the worse for wear, is conspicu- 

 ous ; and, of moths, the cotton-worm moth (Aletia 

 xylina), the army-worm moth (Leucania unipuncta), 

 and Platyhypena scabra, are noteworthy in the 

 south. 



April. — The first flowers of spring, and espe- 

 cially the catkins of willows and poplars, teem with 

 insects of many orders, but especially the Hymenop- 

 tera of the genera Andrena, Halictus, Melissodes, 

 and Nomada, which have issued from their under- 

 ground nests. The honey-bee (Apis mellifica), the 

 carpenter-bee (Xylocopa virginica), and the bumble- 



