BEETLES. gjf) 



of bkick spots, the head and feet are lilaek, and there is a ring of tlie same eolor iijioii 

 the second segment. The head ami legs of JJ. j((nct<i are, on tlic contrary, jiale, and 

 tliey have Imt one row o'l i.ilaek dots on each side. The larvre of the Coloraih_> |ii>tato- 

 beetle attain tlieir full growth in from fourteen to eigliteen days, and go nnder gnnmd 

 to jMipate, where they form a naked yellow pupa. The pupal state lasts ahout ten 

 days, so that only about a month is rei|uired for all stages together, from the eg<4 to 

 the perfect heelles. This enaliles these insects to have from two to four broods yearly, 

 and as the females do not lay their eggs all at one time a succession of larva' is ]iro- 

 duced, so that one may liud the species in every stage of growth at any tinu/ during 

 summer and autumn. JJoth I)eetles and larva' feed on the same [ilant. The beetles 

 hibernate umlergrouud and lay eggs the next spring. 



Tiie iunnense armies of these beetles which have at times attacked potato-fields, 

 where they could be gathered by measure rather than by number, have rendered them 

 a serious pest to farmers, and their actual destruction of whole fields of a vegetable 

 almost necessary to human existence in some countries has caused Doniphora to be 

 the sulijcct of much careful investigation, and of some legislation. Eurojiean nations 

 have sometimes ]>rohibitcd the imjiortation of American potatoes, and fines have been 

 imposed in England for possessing living Colorado potato-beetles. 



The sudden spreading of I). dereinHiieata over an area of about 1,5(10,000 s(juare 

 miles has not only been accom]ianied by a change of food-jilant from one sjiecies of 

 Solanacea' to others, Ijut even to plants of other f.-nnilies. It will eat, when potatoes 

 are not at hand, cabl^age, common thistle {Cirsiuui laiiceolatuin), pigweed {AinaraiUu.f 

 n'/niffe.rii.f), ]n-t^<^c-nmstnril (><l.si/ii//)n'u)n offirmalc), nnd numerous other jilants, and 

 when absolutely compelled by hunger it has been known to eat grass and the cultivated 

 oat. ^fost all widely distril)Uted insects are suliject to considerable variation; the 

 Colorado potat(j-beetle forms no exce[ition, and the fact of its extensive distribution 

 in so short a period as twenty-five years in |iortions of America having considerable 

 diversity of climate, together with the variations consequent upon difference of food- 

 plants to whi<'li it lias accommodated itself, makes these variatii.ms of pattern, color, 

 and size furnish, as Dr. lliley has observed, "interesting material for the close species 

 makers," and indicates a fertile field of investigation of the variations which twentv- 

 five years or less of changed environment can proiluce in a species the whole liistorv 

 of the s])read of wliich is comjiai'atively well reconled. 



As Dori/p/iora itself spreail like a wave of destruction over the countrv, for the 

 first few years its depre(hitions in au}' region were scarcely hindered, but later, while 

 man was learning how to poison it, lower animals were develojiiuo- a taste for it. The 

 lady-birds attack the eggs and larvu' ; mnnerous species of IIemi])tera, sucli as T'oclisus 

 spinost/s and Haipactor cincf/ts, suck out tlu' juices of the larv;-e; a fly (LijcMla dory- 

 phoni') lives in its larval state as a parasite within the larv;p of Doryphora, and has 

 been found so abundant in jilaces as to nearly exterminate the beetle; and the eggs 

 and larva' are eaten by several beetles, among which Ldna grandis — once not verv 

 common — has apparently increased in numbers on account of the food-su]i|ily which 

 Doriiphora furnishes. The above-nicntioiicd iusecfs are selected from over two (hizen 

 species known to attack Doryphora. ,Vmong wild liirds the crow, quail, rose-1>reastcd 

 grosl)eak (Gouhqdica fii<7oriciain/), and cardinal grosbeak {Cardina/is viryinianus); 

 and, among domesticated birds, the duck, di-vour these beetles. In some cases chickens 

 have acquired the habit of feeding up(Ui tlicm, and the connnon toad does a'ood service 

 in eatinsi large numfiers of them. 



