▁after ▁using ▁up ▁their ▁bod ily ▁food ▁stores . ▁ ▁In ▁feed ing ▁on ▁blood , ▁the ▁f lies ▁use ▁their ▁mouth parts ▁to ▁start ▁the ▁host ▁ble eding . ▁They ▁then ▁su ck ▁up ▁the ▁exposed ▁blood . ▁ ▁Like ▁pract ically ▁all ▁blood - feed ing ▁par as ites , ▁they ▁inject ▁bio chem ical s ▁that ▁in hib it ▁blood ▁cl ot ting , ▁plus ▁some ▁that ▁stim ulate ▁host ▁m ast ▁cells ▁to ▁produce ▁hist am ine ; ▁this ▁dist ends ▁cap ill ary ▁vessels , ▁thereby ▁prom oting ▁blood ▁flow . ▁ ▁One ▁blood ▁me al ▁can ▁support ▁the ▁production ▁of ▁about ▁ 1 0 0 ▁eggs . ▁Fem ales ▁lay ▁their ▁eggs ▁in ▁hum id ▁soil ▁rich ▁in ▁organ ic ▁matter . ▁Labor atory ▁colon ies ▁of ▁various ▁ph le bot om ine ▁sand ▁f lies ▁species ▁have ▁been ▁established ▁for ▁experimental ▁study . ▁ ▁Sand ▁f lies ▁are ▁small ; ▁a ▁body ▁size ▁of ▁about ▁ 3 mm ▁in ▁length ▁is ▁typical ▁for ▁many ▁species , ▁which ▁a ids ▁them ▁in ▁esc aping ▁notice . ▁Their ▁b ite ▁is ▁not ▁always ▁felt , ▁but ▁leaves ▁a ▁small ▁round , ▁re dd ish ▁b ump ▁that ▁starts ▁it ch ing ▁hours ▁or ▁days ▁later . ▁ ▁Use ▁of ▁insect ▁rep ell ent ▁is ▁recommended ▁in ▁areas ▁where ▁sand ▁f lies ▁are ▁present . ▁ ▁Distribution ▁ ▁Ph le bot om ine ▁sand ▁f lies ▁can ▁be ▁found ▁between ▁the ▁lat itudes ▁ 5 0 ° N ▁and