INGA 



long to Calliandra. Another allied genus is Pithecolo- 

 bium. Inga has pinnate foliage; the other two genera 

 have bipinnate foliage. In Inga the pod is scarcely or 

 slowly dehiscent: in Calliandra the valves dehisce elas- 

 tically from the apex to the base of the pod and are revo- 

 lute; in Pithecolobium the valves are often twisted, but 

 never rolled back and elastic. 



A. Leaflets liainj beneath. 



affinis, DC. (consult I. dillcis in the supplementary 

 list). Lvs. simply pinnate; If ts. in 4 pairs, ovate, acumi- 

 nate, pubescent above, somewhat shining and villous be- 

 low, one side smaller than the other, 3 in. long, IX in. 

 wide; petioles, branches, peduncles and fls. velvety to- 

 mentose, a gland between each pair of lvs.: spikes soli- 

 tary or in pairs : corollas villous. Trop. Amer.— This is 

 probably the plant cult, in S. Pla. and S. Calif, as /. 

 duleis. 



AA. Leaflets not hairy. 



Feuillei, DC. Lvs. simply pinnatp; Ifts, in 3-t pairs, 

 ovaI-obl"iiK. iii-iitf at both ciicls. ^'hihmus: pods 1-2 ft. 

 loni;. liiii'ar. Hat. f,'lal>n.us, wliiir iiisi,l,>. Peru. — Int. 

 lyiMI liy Krani-fsi-lii. 'Yhv sw.-ri, cMlil.lr |miIi> of the pods 

 is much prized by the Pt-ruviaiis, wli" i-all it Pacay. 



/. anfimain, Kunth. Properly C.-illiamira graiidiflora. Benth. 

 Unarmed: lvs. bipinnate; pinuse 15-I7-paired ; Ifts. more than 

 20-paired, linear, obtuse: petioles not glandular: branches, pe- 

 duncles and lis. puberulous: Hs. rosy: pod linear, acute, nar- 

 rowed at the base, glabrous, thickened at the margin. Trop. 

 Araer.— /. duleis. The older plant of this name is Willdenow's, 

 which comes from the PhiUppines, and is described under Pithe- 

 oolol>ium. I. duleis, of Martius, comes from Brazil, and is I. 

 affinis described above. Franceschi's plant of I. duleis makes a 

 bushy tree, which he says comes from Central America, and 

 has pods containing a white pulp rich in siigar. This plant, he 

 says, grows only in frostless districts, while Inga anomala and 

 pulcherrima will grow where the lemon thrives.—/, pulcker- 

 rima, Cerv. Properly Calliandra Tweediei, Benth. Lvs. bipin- 

 nate: pinnse 3-5-paired; Ifts. as many as 25-paired, paler and 

 slightly hairy beneath : stipules ovato-seariose, brown hairy: 

 peduncle being a head of about 20 fls. Mex. B.M.4188. P.M. 



11:»7- W. M. 



INKBERRY. Ilex glabra. 



INSECTICIDES. Substances used to kill insects, as 

 commonly understood ; but, as defined in dictionaries, 

 "one who or that which kills, or the act of killing an in- 

 sect," constitutes an Insecticide. Hence there are many 

 natural Insecticides, such as winds, rains, sudden 

 changes of temperature, forest and prairie fires, insec- 

 tivorous plants, some bacteria and fungi, several of the 

 higher animals (including man), and many of the in- 

 vertebrates (including spiders and a host of parasitic 

 and predaceous insects). Oftentimes these Insecticides 

 of nature materially aid man in his warfare against in- 

 juriotis insects, but usually it is necessary to resort to 

 a spray or some other artificial Insecticide. 



Insecticides may be classed into those which are 

 eaten with the food and kill by poisoning ; powders, 

 washes and gases which kill by suffocation; and certain 

 oils and soaps which kill when they come in contact 

 with the body, and may also suffocate by closing the 

 breathing holes. The poisons are effective against only 

 the biting or chewing insects, and the sucking insects 

 must be hit with a powder, an oil or soap; or both kinds 

 of feeders may be suffocated with the gaseous Insecti- 

 cides. 



Arsenic is the chief ingredient in most poisonous 

 Insecticides. Its solubility in water, causing it to burn 

 the foliage severely, prevents its being used alone. But 

 by boiling one pound of it with two pounds of lime or 

 four pounds of sal-soda in two gallons of water for 

 half an hour, a very* cheap, effective and reliable In- 

 secticide results ; use about IK quarts to 40 gallons 

 of Bordeaux mixture or water. 



Paris green is still the standard poisonous Insec- 

 ticide, but its cost and adulteration have recently 

 brought several substitutes, such as paragrene and 

 green arsenoid, on the market. London purple is too 

 soluble and variable to give uniform results; hence it 

 is not as much used as formerly. These arsenicals are 

 used at the rate of 1 pound in 'from 100 to 300 gallons 

 of water or Bordeaux mixture on fruit trees, the most 

 dilute on the peach. Arsenate of lead is now largely 



INSECTS 



805 



used against such insects as the gypsy moth and the 

 elm leaf -beetle; large quantities of it can be used on 

 the foliage without injury, and it adheres better than 

 Paris green, but is sometimes more expensive. Helle- 

 bore, the standard currant worm remedy, is especially 

 valuable to use after fruits are more than half grown, 

 when there would be danger from the use of the arseni- 

 cal poisons. 



Tobacco in its various forms is one of the best Insec- 

 ticides for sucking insects; it is particularly useful in 

 greenhouses. Pyrethrum powder is the standard Insec- 

 ticide for house-flies, and is often effectively used 

 against other insects. 



Kerosene is one of the most active and effective of In- 

 secticides. It can rarely be used with safety undiluted, 

 but as an emulsion with soap, it has been the standard 

 remedy for sucking insects for many years. The for- 

 mula is: half a pound of soap, 1 gallon hot water, and 

 2 gallons of kerosene; pour the kerosene into the hot 

 soap solution and agitate violently for a few minutes. 

 Recently, however, manufacturers have devised spray 

 pumps which combine kerosene and water into a good, 

 effective emulsion. These kerowater pumps can be 

 regulated to use certain percentages of kerosene, but 

 they are often unreliable and have not t:ikcn the place 

 of the kerosene soap emulsion. Whal,- i.il >..:ip is now 

 extensively and successfully usr, I in kjlliiiLr ^ -ili- insects 

 and plant-lice. It and the limi-^nHHr ^pr.i> ;n «■ tlie most 

 effective sprays now in use a{;;iiiiNt tin- taiimus ,San Jos^ 

 scale, the pear psylla, and other sucking insects. Crude 

 petroleum has been successfully used in combatting 

 cattle lice and the horn-fly, and is an effective but some- 

 times unsafe sulistance to apply on dormant trees for 

 the San Jos6 and other scales. In California, a resin 

 wash and a lime, salt and sulfur wash are extensively 

 used and found very effective against scale insects; in 

 the E.^st the lime-sulfur wash is also effective. 



Two gases are extensively used in killing insects. 

 The fumes of carbon bisulfide are certain death to in- 

 sects infesting stored grains, seeds or clothing. Place 

 the infested material in a tight box; pour the liquid, at 

 the rate of 1 pound to each 100 bushels, or 1 pound to 

 each 1,000 cubic feet, into shallow dishes placed on top 

 of the materials, and quickly close the box, leaving it 

 for a day or so. The fumes are explosive; hence keep 

 all lights away. This liquid has also been successfully 

 used in treating melon and cucumber vines, under covers 

 for plant-lice. The other gaseous Insecticide is hydro- 

 cyanic acid gas, the uses of which are discussed below 

 under Scale Insects, page 812. 



The arsenical poisons seem to be equally effective 

 when applied in combination with the fungicide Bor- 

 deaux mixture, and most fruit-growers now spray with 

 such a combination. Sometimes one of the Insecticides 

 for killing sucking insects has been successfully mixed 

 with the Bordeaux, but it is doubtful if they are as effec- 

 tive when thus applied. The poisons do not readily 

 mix with the soaps or oils, and, as a rule, one cannot 

 effectively hit sucking insects, biting insects, or the 

 fungous diseases with a single application of some 

 combination mixture. m. y. Slingerland. 



INSECTS. The animals which constitute the Insect 

 world play an important part in most horticultural 

 operations. The busy bee is an indispensable aid in the 

 production of many fruits, but the equally busy .jaws of 

 canker-worms or other Insects oftentimes seriously in- 

 terfere with man's plans for profitable crops. Horti- 

 culturists should become more intimately acquainted 

 with their little friends and foes in the Insect world. 

 Not only from the economic standpoint is this knowledge 

 necessary in the busiii.'>i>< nf nrmving plants, but the 

 striking peculiarities., r r.nn, r,,|,,i m-. structure, habits, 

 and the wonderful tr;i 1 1 i :: i Insects afford one 



of the most interestiiiL : n.-. The life-stories 



of many Insects, if toM m I i i il ,. .iiM rival in variety 

 and interest many a f:ini<.us f:dry tale. The science 

 that treats of Insects, or entomology, has now reached 

 the stage where its devotees are no longer looked upon 

 as "crazy bug-hunters" in most communities. A recent 

 directory of the entomologists, or those interested in 

 the study of Insect life, of the United States and Can- 

 ada contains the names of over 1,200 persons. 



