An unknown number of guns are being built with the mechanisms, causing problems for the police and ATF officials. Photo: An ATF agent holds a generic unfinished receiver, back, and one that has been manufactured, front, at an ATF field office in Washington, on May 06, 2014. The ATF is trying to crack down on the trade in the makeshift guns by targeting shops and individuals who offer to turn the unfinished receivers into functional pieces for firearms. (Photo by Bill O'Leary/The Washington Post)

Thai vendors stand next to edible insects for sale at Talad Thai market in Pathum Thani province on the outskirts of Bangkok, Thailand, 15 July 2013. Insects have long been on the menu in Thailand, but academics and the United Nation's Food and Agriculture Organization (FAO) officials are hoping they will become a more common global source of protein and nutrients to meet the need for growing world food requirements in the future. (Photo by Narong Sangnak/EPA)

Three pugs peer out from a car window in Los Angeles, California. A wacky photographer has come up with an unusual pet project – snapping ecstatic dogs as they hang their heads out of car windows. Lara Jo Regan, 48, embarked on the odd task for her new 2014 calendar “Dogs In Cars”. The unusual shoot, which took place in Los Angeles, California, aimed to explore the joy experienced by pugs and huskies when a breeze hits their faces. (Photo by Lara Jo Regan/Barcroft Media)

The Ivanpah Solar Electric Generating System is seen in an aerial view on February 20, 2014 in the Mojave Desert in California near Primm, Nevada. The largest solar thermal power-tower system in the world, owned by NRG Energy, Google and BrightSource Energy, opened last week in the Ivanpah Dry Lake and uses 347,000 computer-controlled mirrors to focus sunlight onto boilers on top of three 459-foot towers, where water is heated to produce steam to power turbines providing power to more than 140,000 California homes. (Photo by Ethan Miller/Getty Images)

Painted eggshell displayed at Wayan Sadra's workshop on April 14, 2014 in Sukawati, Gianyar, Bali, Indonesia. 50-year-old Wayan Sadra got the idea to start his eggshell painting business, after his niece who worked in a five star hotel asked for his help to paint on an egg for an Easter egg competition. Now the business he started in 1997 attracts customers for his painted eggs from Germany, France, Italy, and the Netherlands. Sadra usually experiences a surge in sales ahead of Easter. (Photo by Putu Sayoga/Getty Images)

A nurse helps an injured bomb victim sitting at the back of a pickup truck at the Asokoro General Hospital in Abuja, April 14, 2014. A morning rush-hour bomb killed at least 35 people at a Nigerian bus station near the capital on Monday, raising concerns about the spread of an Islamist insurgency after the first such attack on Abuja for two years. Suspicion fell on Boko Haram, though there was no immediate claim of responsibility from the Islamist group mainly active in the northeast. Five hours after the blast, officials had given no death toll. Reuters journalists counted at least 35 bodies. (Photo by Afolabi Sotunde/Reuters)

Artist Rachel Stubbs works on the final touches of a sand sculpture she has built as part of this year's “Once Upon a Time” themed annual Weston-super-Mare Sand Sculpture festival on April 16, 2014 in Weston-Super-Mare, England. Due to open on Good Friday, a team of award winning sand sculptors from across the globe have been working to create sand sculptures influenced by fairy tales and fables but that also include some current television and cinema blockbuster hits such as The Hunger Games, Game of Thrones and The Hobbit. (Photo by Matt Cardy/Getty Images)

This undated photograph shows one of the 14 new species of so-called dancing frogs discovered by a team headed by University of Delhi professor Sathyabhama Das Biju in the jungle mountains of southern India. The study listing the new species brings the number of known Indian dancing frogs to 24 and attempts the first near-complete taxonomic sampling of the single-genus family found exclusively in southern India's lush mountain range called the Western Ghats, which stretches 1,600 kilometers (990 miles) from the west state of Maharashtra down to the country's southern tip. (Photo by Satyabhama Das Biju/AP Photo)